Road Statistics 2008: Traffic, Speeds and Congestion

Transcription

1 Road Statistics 2008: Traffic, Speeds and Congestion SB (09) 18

2 A National Statistics publication produced by Transport Statistics: DfT National Statistics are produced to high professional standards set out in the National Statistics Code of Practice. They undergo regular quality reviews to ensure that they meet customer needs. Contact Points: For general enquiries call the National Statistics Customer Contact Centre at: Room 1.015, Office for National Statistics, Cardiff Road, Newport NP10 8XG, telephone: fax: , You can also obtain National Statistics through the internet go to For information relating to Transport Statistics go to Crown copyright 2009 Copyright in the typographical arrangement rests with the Crown. This publication may be reproduced free of charge in any format or medium for research, private study or for internal circulation within an organisation. This is subject to it being reproduced accurately and not used in a misleading context. The material must be acknowledged as Crown copyright and the title of the document/publication specified. This publication can also be accessed at the Department's website. For any other use of this material please apply for a Click-Use Licence at or by writing to OPSI at the Information Policy Team, Office of Public Sector Information, Kew, Richmond, Surrey TW9 4DU or to licensing@opsi.x.gsi.gov.uk Further information and queries concerning this publication should be directed to: SR2, 3/17 Great Minster House, 76 Marsham Street, London SW1P 4DR +44 (0) , Fax +44 (0) , roadtraff.stats@dft.gsi.gov.uk Brief extracts from this publication may be reproduced provided the source is fully acknowledged. Proposals for the reproduction of larger extracts should be addressed to the Department at the following address: Department for Transport (DfT), Transport Statistics, 2/29, Great Minster House, 76 Marsham Street, London SW1P 4DR , Fax: , taj.gul@dft.gsi.gov.uk Printed in the United Kingdom on material containing 100% post-consumer waste. Symbols and conventions: (i) Unless otherwise stated, all tables refer to Great Britain. (ii) Metric units are generally used. Units: Figures are shown in italics when they represent percentages, indices or ratios. Rounding of figures: In tables where figures have been rounded to the nearest final digit, there may be an apparent slight discrepancy between the sum of the constituent items and the total as shown. Conversion factors: 1 kilometre = mile 1 tonne = ton 1 tonne-km = ton-mile 1 gallon = litres 1 billion = 1,000 million 1 litre = gallons Symbols: The following symbols have been used throughout... = not available. = not applicable - = Negligible (less than half the final digit shown) 0 = Nil * = Sample size too small for reliable estimates. ow = of which { = subsequent data is disaggregated } = subsequent data is aggregated = break in the series P = provisional data F = forecast expenditure e = estimated outturn n.e.s = not elsewhere specified TSO = The Stationery Office

3 Road Statistics 2008: Traffic, Speeds and Congestion Department for Transport June 2009

4 Contributors Department for Transport Statistics Roads Division Anthony Boucher June Bowman Barbara Noble Road Traffic and Road Length Statistics Drew Hird Daryl Lloyd William Rose Hiten Shah Automatic Traffic Counters and Weigh In Motion Development Statistics Steve Dennis Andy Lees Inter-Urban Congestion Statistics Ian Grieve Sophie Riley David Robinson Dorothy Salathiel Urban Congestion Statistics Eric Crane William Laffan Craig Medhurst Vehicle Licensing Statistics - Statistics Travel Division Osman Beg Ben Coleman 2

5 Road Statistics 2008: Traffic, Speeds and Congestion Contents Special Note 4 1. Introduction 6 2. Trends in Traffic Overview Car traffic growth over time Traffic and fuel prices Spatial distributions of traffic flows and traffic growth Road Traffic in Great Britain Trends in road traffic Motor vehicle flows Foreign registered vehicle estimates Road lengths Goods vehicle traffic Free Flow Vehicle Speeds in Great Britain Introduction Non-built-up roads Built-up roads Exceeding the speed limit: 1998 to Congestion and Traffic Speeds on the Inter-Urban 42 Road Network in England 5.1 Journey time reliability Traffic speeds Congestion and Traffic Speeds in English Urban Areas Congestion Journey speeds and variability Journey times by time of day 64 Glossary 67 3

6 Special Note United Kingdom Statistics Authority and National Statistics 1. National Statistics are produced to high professional standards set out in the National Statistics Code of Practice. They undergo regular quality reviews to ensure that they meet customer needs. They are produced free from any political interference. 2. Since April 2008, the United Kingdom Statistics Authority (UKSA) has had the responsibility for monitoring, assessing and reporting on all official statistics, including all statistics with the National Statistics mark. 3. Most of the statistics presented in this publication (Road Traffic in Great Britain, Free Flow Vehicle Speeds in Great Britain and Congestion and Traffic Speeds on the Inter-Urban Road Network) are National Statistics and adhere to the National Statistics Code of Practice. These chapters contain 2008 data released for the first time. 4. Chapter 6, Congestion and Traffic Speeds in English Urban Areas, and Section 3.3 providing estimates of foreign registered vehicles present 'experimental statistics' that are under development. These are still official statistics, but are currently undergoing testing of their ability to meet customer needs. The Department believes they are robust enough to give a reasonable indication of overall trends, but while the series are experimental their quality cannot be assured to the rigorous standards required by National Statistics. Road lengths 5. The Department for Transport (DfT) bases its road length estimates on data provided by Ordnance Survey. In 2006 DfT switched from using Ordnance Survey's OSCAR roads data set to the ITN data set in calculating the length of B roads and unclassified roads. 6. In 2004 amendments were made to the data for roads in Scotland where some private roads (predominantly those for which the Forestry Commission is responsible) were previously incorrectly recorded as public roads. Quality review 7. The Review of Road Traffic and Road Length Statistics (National Statistics Quality Review Series Report 49) was published in January 2007 and is available from the National Statistics website: Work is now taking place through the Traffic Estimates Improvement Programme to implement the recommendations in the review. In addition other areas for development have been identified and explored. 4

7 Local Authority level statistics 8. Estimates of road traffic at local authority level, together with corresponding figures for casualties in road accidents, will be made available on the DfT web site. They are provided to enable the calculation and monitoring of road casualty rates for individual local authorities. These traffic figures are less robust than the regional and national totals and are not classed as National Statistics. National events affecting traffic 9. In 2000, the September fuel dispute led to a decline in car and taxi traffic for that year. The widespread outbreak of Foot and Mouth disease in 2001 and the control measures put in place also had an effect on traffic. 5

8 Introduction 1 Introduction This is the third bulletin in an annual series bringing together statistics on traffic, road lengths, vehicle speeds and congestion in Great Britain. These statistics are used for a variety of purposes within government, informing policy and providing the source data for analytical research. One of the main uses of the traffic estimates is to feed directly into the National Transport Model, which is used to compare the likely impact of alternative national transport policies. Traffic estimates and congestion data are widely used outside the Department for Transport (DfT) by researchers, local authorities, businesses and the public. 1.1 Traffic Traffic data are collected continuously from a national network of approximately 180 Automatic Traffic Counters (ATC). In addition to counting traffic, the ATCs also record some of the physical properties of passing vehicles (which are used to classify traffic by type) and vehicle speeds. Provisional traffic estimates derived from the ATCs only are published quarterly. The 2008 annual estimates published here are mainly based on manual counts at approximately ten thousand sites, which are combined with ATC data and road lengths to produce overall estimates. 1.2 Speeds This bulletin contains two different types of speed data. The first is free flow speed data obtained from the network of around 100 ATCs. The ATCs are sited at points where traffic is not congested under normal conditions. These free flow speeds give important information on compliance with speed limits. The second type of data are used to measure congestion in urban areas and on inter-urban roads. The data include information on speeds from anonymised data from ATCs, Automatic Number Plate Recognition (ANPR) cameras, and Global Positioning System (GPS) units in vehicles. These new sources replace the previous floating car surveys, and have much larger sample sizes, enabling more roads to be covered at greater precision, and over a greater proportion of the week. 1.3 Congestion One of the five strategic aims of DfT is: To support national economic competitiveness and growth, by delivering reliable and efficient transport networks. It is therefore important for the Department to be able to measure how efficiently the road network is performing using clearly established measures of congestion. Congested roads lead to longer delays and greater inconsistencies in journey times, 6

9 Introduction therefore a congested road is less efficient and less reliable than a road with free flowing traffic. Congestion is easily recognised by those experiencing it, but less easily defined. It should be noted that changes in traffic are not directly related to changes in congestion. On some quiet roads, traffic can increase substantially with little effect on congestion. On roads where traffic is on the threshold of capacity, a small change in traffic can lead to large changes in congestion. Other road conditions, such as road works, can also affect the capacity of roads. The relationship between traffic growth and congestion over a network (such as the motorway and trunk A road network) is not well understood and research is in progress to explain this relationship. DfT has two Public Service Agreements (PSA) relating to congestion on inter-urban and urban roads. Congestion on inter-urban roads The inter-urban road network in England consists of all motorways and trunk A roads managed by the Highways Agency, as well as the M6 Toll. This is also known as the Strategic Road Network (SRN). Congestion on the SRN is defined as the average vehicle delay, derived from the differences between observed journey times and a reference journey time (the time that could theoretically be achieved when the traffic is free flowing). DfT measures the average vehicle delay on the slowest 10% of journeys on each of 95 routes on the SRN to track progress on its PSA to minimise increases in delay on the SRN between years ending March 2008 and March There is no specific numerical target. The data used to measure congestion on inter-urban roads are published monthly as National Statistics on the DfT website. Congestion in urban areas DfT has a PSA target on urban congestion which states: By , the ten largest urban areas will meet the congestion targets set in their local transport plan relating to movement on main roads into city centre. The target will be deemed to have been met if, on target routes in the ten largest urban areas in England, an average increase in travel of 4.4 per cent is accommodated with an average increase of 3.6 per cent in person journey time per mile. Data from GPS units in vehicles are used to monitor progress, which is published quarterly. 7

10 Introduction Figure 1.1 illustrates the geographical extent of the two congestion PSA measures. The built-up settlements of the ten urban congestion areas are shown. The monitored routes in some areas extend beyond the administrative boundaries, as shown in more detail in the maps in Chapter 6. Figure Inter-urban routes and urban areas used for congestion monitoring, England:

11 Introduction 1.4 Further available data The full tables of roads traffic data, previously published as Road Traffic Statistics, the full tables of the free flow vehicle speeds data, previously published as Vehicle Speeds in Great Britain, and the full congestion data tables, maps and charts are available on the web annex to this publication: n/roadstatstsc/roadstats08tsc. The most recently available Annual Average Daily Flows, by vehicle type, for individual major road links are available from the DfT Matrix website: More information on congestion on inter-urban roads and the Department s Public Service Agreement to tackle congestion can be found on the DfT website: n/congestiononthestrategicroad5359. Information on road traffic in Great Britain, congestion on inter-urban roads and congestion in urban areas is published quarterly in the transport statistics bulletin Road Traffic and Congestion in Great Britain, and can be found on the DfT website: More information and data covering the range of DfT statistics, including the series that this publication replaced (Road Traffic Statistics, Vehicle Speeds in Great Britain, Traffic Speeds on English Trunk Roads, and Traffic Speeds in English Urban Areas) for earlier years, can be found on the DfT website: Enquiries and feedback More detailed information on traffic estimates by type of vehicle and class of road, traffic speeds or congestion are available from DfT. Enquiries should be made to Statistics Roads: Road Traffic and Road Length Statistics branch at the following address: roadtraff.stats@dft.gsi.gov.uk Department for Transport Statistics Roads 2 Branch Zone 3/17, Great Minster House 76 Marsham Street LONDON, SW1P 4DR Enquiries about the contents of this document should also be made to the above address. Any comments or feedback on this publication can also be sent to this postal or address. 9

12 Trends in traffic 2 Trends in traffic This chapter looks at the changing trends in road traffic over time and possible factors driving these changes. Additional analysis of trends in traffic can be found in last year s edition of this bulletin Overview What is traffic and how are traffic data collected? Traffic is measured in vehicle kilometres, where one vehicle kilometre is equal to a single vehicle travelling one kilometre. This gives an estimate of the total distance that all the vehicles in the country have driven during the year. The 2008 annual estimates published here are mainly based on manual counts at approximately ten thousand sites, which are combined with data from Automatic Traffic Counters (ATCs) and road lengths to produce the overall estimates for Great Britain. Traffic data are collected continuously from approximately 180 ATCs which classify traffic by vehicle type by recording physical properties of vehicles. The ATCs also record vehicle speed. In addition to the annual data published here, provisional quarterly traffic estimates based mainly on the ATCs are published in the quarterly bulletin Road Traffic and Congestion in Great Britain. Overall Trends 2008 saw the first year on year fall in overall motor vehicle traffic (0.8 per cent) since the 1970s. This fall was probably due to a combination of higher fuel prices, which peaked in July, and the economic slowdown which turned into a recession during the second half of the year. Figure 2.1 shows how the volume of traffic in Great Britain has grown over time. The long term trend of growth in traffic over time has mainly been a result of growth in car ownership, as will be discussed in Section 2.2. Figure All motor vehicle traffic, Great Britain: 1950 to Cars and taxis Other Billion vehicle kilometres The bulletin Road Statistics 2007: Traffic, Speeds and Congestion can be found at: ats07tsc. 10

13 Trends in traffic Figure Traffic by vehicle type, Great Britain: 1980 to Cars and taxis Other 120 Light vans Buses and coaches Pedal cycles Heavy goods vehicles Motor cycles Billion Vehicle Kilometres Figure 2.2 above shows the distribution of traffic among different vehicle types from 1980 to Since 1980, cars have accounted for around 80 per cent of all motor vehicle traffic and have therefore been the main driver of traffic growth. However, light van traffic has shown consistent strong growth between 1993 and 2008, while car traffic growth has been slowing over time, which is why light vans are becoming increasingly important as a driver of overall traffic growth. More analysis of trends in goods vehicle traffic growth can be found in last year s edition of the bulletin. Figure Year on year growth in all motor vehicle traffic, Great Britain: 1950 to 2008 Year-on-year growth (%) Suez crisis OPEC oil embargo Strong economic growth 1990s recession Fuel Protests Fuel price spike and the start of a recession Figure 2.3 shows how the long term trend in traffic growth has slowed over time. Traffic growth is affected by a mixture of long term and short term factors. Some of the key events which have had an impact on traffic growth are shown above and are discussed later in the chapter. Section 2.2 discuses reasons for the changing trend in car traffic and Section 2.3 discusses the effect of varying fuel prices. How traffic is spatially distributed and differing growth rates in urban and rural areas are discussed in Section

14 Trends in traffic 2.2 Car traffic growth over time As shown in Figure 2.4, although the overall volume of car traffic has grown since 1950, the actual rate of growth (as shown by the blue line) has been slowing over time. This section explores possible reasons behind this changing trend. Figure Car traffic volume and year on year growth rate, Great Britain: 1950 to 2008 Car traffic (left scale) Year on year growth rate (right scale) Billion vehicle kilometres Growth in car traffic has in part been due to the growing population. To remove this effect, per person growth rates can be used. An increase in car traffic can occur through either more cars being driven or through each car being driven more. Therefore car traffic per person can be thought of as the combination of two elements: the number of licensed cars per person and the distance driven per car. Figure 2.5 shows the estimated contributions made by changes in the number of cars per person and the distance driven per car to year on year growth in car traffic per person. For most years the contribution from changes in the number of cars per person has been larger than the contribution from the distance driven per car. This shows that over time car traffic has been mainly driven by growth in car ownership. Figure Contributions from changes in cars per person and distance driven per car to year on year growth in car traffic per person, Great Britain: 1951 to Cars per person contribution Total annual growth in car traffic per person Year on year growth (%) Distance driven per car contribution Percentage points contributed

15 Trends in traffic Growth in the number of licensed cars per person As car ownership has become more saturated car ownership growth has slowed, as shown in Figure 2.6. This has led to much of the slowing of the growth in car traffic per person over time. According to the National Travel Survey (NTS) 2, there is still room for further growth, with a quarter of households without access to a car in Car ownership growth now appears to moving broadly in line with GDP growth. Figure The number of licensed cars per person and GDP per person, year on year growth, Great Britain: 1980 to 2008 Year on year growth (%) Licensed cars per person GDP per capita Changes in distance driven per car Alongside the slowing rate of growth of cars per person, since the start of the 1990s car traffic growth has been markedly lower due to falling distance driven per car, as shown in Figure 2.5. Data from the NTS show a similar picture, with the average annual distance driven among licence holders with access to a household car also falling. Rising fuel prices are a possible explanation for this trend (as discussed in Section 2.3) and the recession of the early 1990s may have resulted in some ongoing change in travel behaviour. In addition, the growth in rail and aviation use may have meant the longest car trips from the past being undertaken by train or plane. The increasing proportion of households with more than one car may also make some contribution to the falls in distance driven per car. For example, if a household with one car were to get a second car, the overall distance driven by members of the household may increase but would not necessarily double. Therefore the total distance driven would be shared out between more cars, resulting a shorter distance per car. 2 Further information about the National Travel Survey can be found at: 13

16 Trends in traffic 2.3 Traffic and fuel prices Fuel prices were probably a key factor behind the 0.6 per cent fall in car traffic between 2007 and This section looks at the impact fuel prices may have been having on traffic over time. There have been three notable spikes in fuel prices coinciding with falls in overall traffic: , , and The 2000 spike coincided with no overall growth in traffic. Figure Fuel prices, Great Britain: 1955 to 2008 Petrol prices 130 Suez crisis 120 OPEC oil embargo 110 Pence per litre (2008 prices) Diesel prices Fuel protests Source: Department for Business Innovation & Skills; Office for National Statistics No annual figures for fuel prices are available prior to 1978, so averages between successive January figures have been used. Often during spikes in fuel prices the events surrounding the spikes may have more of an impact on traffic than the price of fuel itself: The spike Suez Crisis. There was a 0.7 per cent fall in traffic between 1956 and Fuel shortages led to fuel rationing from January to May A cut in oil supplies to industry led to a four day working week in many factories. Driving tests were suspended between November 1956 and April The Oil Crisis OPEC oil embargo for some countries (not including the UK) and steep price rises for the rest. Also the National Union of Mineworkers staged a work to rule (working no longer than minimum hours) in response to pay caps introduced to curb inflation. There was a 1.8 per cent fall in traffic between 1973 and A three day working week was imposed from January to April 1974 to conserve energy. There was a recession in The 2000 spike resulted in fuel protests. There was no overall traffic growth between 1999 and A group of British hauliers blockaded British oil refineries in September 2000, which, together with panic buying, resulted in fuel shortages. 14

17 Trends in traffic Therefore, looking at specific years when fuel prices have been particularly high is not necessarily a good indication of how fuel prices affect traffic. It is reasonable to expect traffic growth, in the short term, to be lower when fuel prices are higher. However, the extent to which this is true varies across time and in the long term other factors may be more important such as population growth, economic growth and changes in public transport. Figure 2.8 shows how falling car traffic in 2008 coincided with a spike in fuel prices. Although fuel prices may have been a key factor in 2008, the economic downturn was also probably an important factor, and it is difficult to separate out the two effects. Fuel prices have now returned to 2007 levels and the national forecasts 3 suggest that car traffic growth will resume once the recession has passed. Figure Year on year growth in car traffic and fuel prices, Great Britain: Q to Q Year on year growth in car traffic Fuel prices Year on year growth in car traffic (%) Q Q The fuel protests Q Q Q Q Q Q Q Q Fuel prices index: 1999 = The 2008 car traffic growth figures are based on the provisional quarterly 2008 estimates which have been scaled up to reflect the 2008 annual traffic estimates. Final 2008 quarterly traffic estimates will be published in August 2009 in the quarterly bulletin Road Traffic and Congestion in Great Britain. 3 The national traffic forecasts can be found at: 15

18 Trends in traffic 2.4 Spatial distributions of traffic flows and traffic growth As every link on the motorway or A road network has an average daily flow, it is possible to produce a more detailed spatial picture. The map in Figure 2.9 shows the estimated density of motor vehicles per kilometre of land in Areas that are coloured dark brown have a number of high flow links near each other. The light brown and white areas have much lower densities of links, or only links with low flows. It is clear that the areas of Great Britain with the highest flow densities are in and around larger urban settlements. In particular, Greater London and the smaller conurbations of Birmingham, Manchester, Newcastle upon Tyne and Glasgow are easily identified. All of these areas have a very high volume of vehicles travelling on a dense network of motorways and A roads that are required to support relatively high densities of residential population. As found in Section 3.4, motorways carry 20 per cent of all traffic, although they only account for 1 per cent of the road length. Many of the busier motorways and A roads have such a high traffic flow density that individual routes can be identified. Examples of this can be seen following the line of M1 north from London to Yorkshire, the line of the A1 north to Newcastle upon Tyne, and the M6 between Birmingham and Warrington. Many of these busier routes are part of the Strategic Road Network discussed in Chapter 5. The importance of urban traffic can be viewed in other ways. Excluding motorway traffic, in 2008 urban roads carried 47 per cent of all traffic in Great Britain and rural roads carried the remaining 53 per cent. In terms of road lengths, however, urban roads only accounted for 36 per cent of all roads, and urban areas themselves only covered about 4 per cent of the British landmass. In addition, about 70 to 80 per cent of the population live within the same urban areas. This gives some indication of why there appears to be such a high density of traffic at these locations. As discussed in Road Statistics 2007: Traffic, Speeds and Congestion, over recent years urban A roads have undergone significantly lower growth than rural A roads. The most recent figures for 2008 show the same pattern. Since 1998 traffic on rural A roads has increased by 11 per cent. During the same period, traffic on urban A roads has decreased by almost 2 per cent. Further to this, between 2007 and 2008 traffic on minor urban roads fell by 1.5 per cent whilst traffic on minor rural roads rose slightly. The differences in traffic growth between urban and rural roads may be explained by capacity constraints and public transport in urban areas together with higher population growth in rural areas. For a more detailed discussion of this issue please see Section 1.5 in last year s publication. 16

19 Trends in traffic Figure Major roads motor vehicle traffic flow density, Great Britain:

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21 Road Traffic in Great Britain 3 Road Traffic in Great Britain Between 2007 and 2008, total estimated motor vehicle traffic fell by 4.1 billion vehicle kilometres (0.8 per cent) to billion vehicle kilometres. This is the first fall since 1979, but an 11 per cent increase over the decade from Car traffic still accounts for the most significant share of the overall traffic, making up 79 per cent of all motor vehicle traffic. In 2008 car traffic was billion vehicle kilometres. This is a 0.6 per cent decrease from 2007, and is up by 8.4 per cent since In 2008, light van traffic fell for the first time since Light van traffic was 68.1 billion vehicle kilometres, a 0.4 per cent decrease from Total heavy goods vehicle (HGV) traffic in 2008 was 28.7 billion vehicle kilometres; this represented a 2.2 per cent decrease from 2007 and a 3.6 per cent increase over the ten years since In 2008, 28 per cent of traffic was on rural A roads, 22 per cent on urban minor roads, 20 per cent on motorways, 16 per cent on urban A roads and 14 per cent on rural minor roads. About 1 kilometre in every 250 kilometres was estimated to be driven by foreign registered vehicles in 2008 (0.4 per cent of British traffic). In 2008, the South East of England was responsible for 17 per cent (87.1 billion vehicle kilometres) of all motor vehicle traffic in Great Britain. The total road length in Great Britain in 2008 was estimated to be thousand kilometres. Motorways accounted for 0.9 per cent, A roads 11.8 and minor roads 87.3 per cent of the total. 19

22 Road Traffic in Great Britain 3.1 Trends in road traffic This section provides details of traffic estimates for Great Britain, which gives the number of vehicle kilometres travelled in any given year by vehicle type, road class and region. More information on the measurements of traffic and the definitions of vehicle types and road classes used here is given in the glossary. Road traffic by vehicle type The overall motor vehicles traffic estimate fell by 4.1 billion vehicle kilometres (0.8 per cent) from 2007, to billion vehicle kilometres in This is the first fall since From 1998 to 2008 overall traffic increased by 11 per cent. Car traffic fell to billion vehicle kilometres in 2008 and accounted for 79 per cent of total motor vehicle traffic. This is a 0.6 per cent fall from In 2008, light van traffic was 68.1 billion vehicle kilometres. This is a 0.4 per cent fall from 2007, and a 34.1 per cent rise since Heavy goods vehicle (HGV) traffic decreased by 2.2 per cent from 29.4 billion vehicle kilometres in 2007 to 28.7 billion vehicle kilometres in In 2008, two-wheeled motor vehicle traffic was estimated to be 5.1 billion vehicle kilometres, 8 per cent lower than in Table Road traffic by vehicle type, Great Britain: 1955 to 2008 Cars and taxis Motorcycles etc. Buses and coaches Light vans Heavy goods vehicles Billion vehicle kilometres All motor vehicles Pedal cycles Source: National Road Traffic Survey, Department for Transport. 20

23 Road Traffic in Great Britain Figure 3.1a - Growth in traffic by vehicle type (private vehicles), Great Britain: 1998 to Traffic Volume Index: 1998 = Motorcycles etc. Pedal cycles All motor vehicles Cars and taxis Source: National Road Traffic Survey, Department for Transport. Figure 3.1b - Growth in traffic by vehicle type (commercial and public service vehicles), Great Britain: 1998 to Traffic Volume Index: 1998 = Light vans All motor vehicles Heavy goods vehicles Buses and coaches Source: National Road Traffic Survey, Department for Transport. 21

24 Road Traffic in Great Britain Motor vehicle traffic by road class In 2008, 28 per cent of traffic was on rural A roads, 22 per cent on urban minor roads, 20 per cent on motorways, 16 per cent on urban A roads and 14 per cent on rural minor roads. Traffic on motorways decreased by 0.4 per cent between 2007 and 2008, while traffic on urban A roads decreased by 1.6 per cent and traffic on urban minor roads decreased by 1.5 per cent. Since 1998 rural A road traffic has increased by 11.0 per cent, while urban A road traffic has decreased by 1.6 per cent. Road traffic by country and Government Office Region In 2008, almost 86 per cent of traffic in Great Britain was in England. Scotland had 9 per cent of the traffic and Wales 6 per cent. The busiest region in Great Britain was the South East of England with 17 per cent of traffic. The North East of England was the least busy, with 4 per cent of traffic. Table Motor vehicle traffic by road class, country and Government Office Region: 2008 Major roads 'A' roads Motorway Rural Urban All 'A' roads Minor roads All major roads Rural Urban Billion vehicle kilometres All minor roads All roads North East North West Yorkshire and The Humber East Midlands West Midlands East of England London South East South West England Wales Scotland Great Britain Source: National Road Traffic Survey, Department for Transport. 22

25 Road Traffic in Great Britain 3.2 Motor vehicle flows The previous section looked at the volume of traffic (vehicle kilometres) within the year. This section looks at average daily traffic flows. The motorways and A roads in Great Britain have been split up into separate links defined by junctions with other major roads. For each of the links, the Department has calculated the average number of vehicles passing a particular point on the link for an average day in the year: the average daily flow. The average daily flow produced for a single point on a single road includes traffic travelling in both directions. Flows for links of a similar road type can be grouped together to give an average across the whole road type; these are presented below. The average daily flows for individual road links are available on the Department s website 4. Motor vehicle flow by road class Motorways had the highest average traffic flow in 2008 at 76.9 thousand vehicles per day. This represents a 0.7 per cent decrease since 2007, and a 12 per cent increase since The average traffic flows on urban A roads have fallen by 2.5 per cent over the past ten years, while flows on rural A roads have increased by 10 per cent and on rural minor roads by 16 per cent since In 2008, the average major road in Great Britain had almost 12 times the flow of the average minor road. Table Motor vehicle flow by road class, Great Britain: 1998 to 2008 Major roads 'A' roads Motorway Rural Urban All 'A' roads Minor roads All major roads Rural Urban Thousand vehicles per day All minor roads All roads Source: National Road Traffic Survey, Department for Transport. 4 Average daily flows for individual links are available at 23

26 Road Traffic in Great Britain Motor vehicle flows for major sections of the motorway network Figure 3.2 shows the average daily flow on some sections of the motorway network. These sections of motorway are illustrative of the type of motorways found around Great Britain. Each section comprises a number of links, for which an average daily flow has been produced. The busiest section of motorway in 2008 was the M25 western links with an average daily flow of 144 thousand vehicles. The traffic flow on this section of motorway fell by 2.3 per cent from 2007 but was 1.5 per cent higher in 2008 than it was in Figure Average vehicle flows for major sections of the motorway network, Great Britain: 2004 and 2008 M25 - Western links from A1(M) to M23 M25 - Eastern links from A1(M) to M23 M60 M6 - South of the M62 junction M62 - East of The Pennines (junction 22) M1 - North of M6 junction M27 M42 M1 - South of M6 junction M4 - England M56 M23 M3 M40 M5 M62 - West of The Pennines (junction 22) M8 M4 - Wales M11 M20 A1(M) M6 - North of the M62 junction M2 M73 M77 M74 M Average flow (thousand vehicles per day) 24

27 Road Traffic in Great Britain Figure Motorways and Trunk Roads, Great Britain: 2008 Note: There are no trunk roads in Shetland (omitted from the map). 25

28 Road Traffic in Great Britain 3.3 Foreign registered vehicles in Great Britain traffic Foreign registered vehicles in traffic by road type The traffic estimates provided throughout this chapter refer to all traffic on the road, regardless of the national origin of the vehicle. During the 2008 Vehicle Excise Duty Evasion survey carried out in June 2008, information was collected about the number of vehicles with registration marks originating outside the United Kingdom. From these figures estimates of the prevalence of foreign registered vehicles on Britain s roads have been made. This is the second time that such statistics have been produced from this survey, the first being published in Road Statistics Therefore the estimates should still be treated with caution at this stage. These statistics are not designated National Statistics and are based on 7,853 observations of foreign registered vehicles from the roadside survey. In 2008, 0.4 per cent of British traffic was estimated to be driven by foreign registered vehicles, compared to a figure of 0.5 per cent in Relating this rate to the vehicle traffic figures, about 1 kilometre in every 250 kilometres driven on Britain s roads was by foreign registered vehicles. In 2007, this ratio was about 1 in every 215 kilometres. There was a significant difference in the percentage of foreign registered vehicles in traffic on different roads. The highest estimated percentage of foreign registered vehicles was on motorways, at 1 in every 125 kilometres being driven by foreign registered vehicles. The lowest percentage of foreign registered vehicles in traffic was on urban minor roads, where it is estimated that foreign registered vehicles only accounted for about 1 kilometre in every 1,400 kilometres driven. A similar pattern was observed in 2007, although the rate of foreign registered traffic has decreased on motorways and urban A roads in the last year. Figure Proportion of foreign registered vehicles in GB traffic, by road type: 2008 Proportion of foreign vehicles registered in traffic (%) Motorw ay Rural 'A' Urban 'A' Rural Minor Urban Minor All roads 26

29 Road Traffic in Great Britain Foreign registered vehicles in traffic by region and road type The South East of England had the highest overall rate of foreign registered vehicles in traffic, estimated at about 0.6 per cent, whilst the North East had the lowest rate, estimated at about 0.2 per cent. Across the country, the highest rate was found on motorways in the East of England where it is estimated that about 1.6 per cent of traffic had non-british registration marks. Motorways in the South East were the second highest, with an estimated 1.3 per cent of traffic being foreign registered vehicles. The regions with the highest rates contain the main entry points to Great Britain through ports or the Channel Tunnel. Minor urban roads in the North East and North West of England, West Midlands, East of England and Wales and minor rural roads in West Midlands, all had estimated rates of foreign registered vehicles in traffic below 0.05 per cent. Overall, comparing 2008 figures to 2007, the rate of foreign registered vehicles in traffic decreased in England and Scotland but increased in Wales. Figure Proportion of foreign vehicles in GB traffic, by country and region: 2008 Proportion of foreign vehicles in traffic (%) North East North West Yorkshire and The Humber East Midlands West Midlands East of England London 7 Table Proportion of foreign registered vehicles in GB traffic, by country, region and road type: 2008 Percentages Major roads 'A' Roads Minor Roads Region Motorway Rural Urban Rural Urban All roads North East North West Yorkshire and The Humber East Midlands West Midlands East of England London South East South West England Wales Scotland Great Britain South East South West England Wales Scotland Great Britain 27

30 Road Traffic in Great Britain Foreign registered vehicles in traffic by body type and region In 2008, 3.5 per cent of all heavy goods vehicle (HGV) traffic in Great Britain was estimated to be driven by foreign registered vehicles. This was the highest proportion by body type and is equivalent to foreign HGVs accounting for 1 kilometre in every 30 kilometres travelled by all HGVs. The lowest proportion of traffic, by body type, accounted for by foreign registered vehicles was cars, estimated at about 0.3 per cent. This is equivalent to 1 kilometre of every 360 being traversed by foreign registered cars. There was a significant regional difference in the percentage of foreign registered vehicles in traffic by body type. The estimated rate of foreign cars in traffic ranges from 0.2 per cent to 0.4 per cent, whereas the rate for foreign HGVs ranges from 1.6 per cent to 5.8 per cent. Across the country, the highest rates of foreign registered vehicles amongst HGV traffic were found in the East and South East of England, estimated at 5.8 and 5.3 per cent respectively. Figure Proportion of foreign registered vehicles in GB traffic, by body type: 2008 Proportion of foreign vehicles in traffic (%) Cars Light Vans Heavy Goods Vehicles Buses & Coaches Table Proportion of foreign registered vehicles in GB traffic, by country, region and body type: 2008 Percentages Heavy goods Buses & Region Cars Light vans vehicles coaches North East North West Yorkshire and The Humber East Midlands West Midlands East of England London South East South West England Wales Scotland Great Britain

31 Road Traffic in Great Britain 3.4 Road Lengths Previous sections of this chapter provide traffic estimates. In order to calculate these it is necessary to have accurate and up-to-date information on road lengths by road class. The road lengths produced are the sum of all the roads maintained at public expense. The lengths are derived from Ordnance Survey data and information provided to the Department by local authorities. Road lengths by road class The total road length in Great Britain in 2008 was estimated to be thousand kilometres. This is an increase of nearly six thousand kilometres (1.5 per cent) over the ten years from Over five thousand kilometres of the additional length has been on the minor road network; most of this increase will have been through the construction of new housing areas. In 2008, motorways and A roads accounted for 0.9 per cent and 12 per cent respectively of the road length in Great Britain. In contrast, 20 per cent of all traffic was on motorways and 44 per cent on A roads. The minor (i.e. B, C and unclassified) road length in Great Britain was estimated to be thousand kilometres, amounting to 87 per cent of the total. These roads carried 37 per cent of all traffic. Excluding motorways, 64 per cent of the roads in Great Britain were in rural areas, whilst the remaining 36 per cent were in urban areas. Figure Percentage of road lengths and traffic by road class, Great Britain: 2008 (a) Percentage of road lengths in Great Britain by road class: 2008 (b) Percentage of traffic in Great Britain by road class: 2008 Urban Minor 33% Motorway 1% Rural A Roads 9% Urban A Roads 3% Urban Minor 22% Motorway 20% Rural Minor 14% Rural A Roads 28% Rural Minor 54% Urban A Roads 16% 29

32 Road Traffic in Great Britain 3.5 Heavy Goods Vehicle Traffic This section focuses on HGV traffic (goods vehicles over 3,500 kgs). Accurate information on goods vehicle traffic is important because of the critical role that the movement of goods plays in the economy. Over the last decade, about 82 per cent of the annual freight, by tonnes lifted, has been carried by road, and HGVs have accounted for about 6 per cent of traffic each year. There are two main types of HGV rigid lorries and articulated lorries. These can be differentiated further by the number of axles on the vehicle. The type of vehicle and the number of axles determines the maximum legal weight for driving on British roads. Traffic flows of goods vehicles by axle configuration Total HGV traffic in 2008 was 28.7 billion vehicle kilometres; this represented a 2.2 per cent decrease from 2007 and a 3.6 per cent increase over the ten years since Rigid axle HGVs drove 14.6 billion vehicle kilometres in 2008 (51 per cent of the total HGV traffic), which is a decrease of 1.8 per cent from Articulated axle lorry traffic decreased from 14.5 to 14.1 billion vehicle kilometres from 2007 to Rigid two-axle HGVs accounted for 37 per cent of all HGV traffic, the highest proportion of all lorry types. The largest type of lorry on British roads, articulated vehicles with six or more axles, accounted for 21 per cent of the heavy goods vehicle traffic in Motorways carried the greatest volume of HGV traffic in 2008 at 42 per cent of all HGV traffic. Minor roads only accounted for 13 per cent of HGV traffic, though almost all of this was rigid lorries rather than articulated lorries. Table Heavy goods vehicle traffic by axle configuration and road class, Great Britain: 2008 Percentage / Billion vehicle kilometres Rigid HGVs by number of axles Articulated HGVs by number of axles Four or Three Six or All Two Three more Total and Four Five more Total HGVs Motorways Rural 'A' roads Urban 'A' roads All major roads Rural Minor Urban Minor All minor roads All roads (Billion vehicle kms)

33 Road Traffic in Great Britain 3.6 Further Information The full tables of traffic and road length data from this chapter are available in the web annex to this publication. The annex includes additional tables on traffic by road class; flow by road class, country and Government Office Region; traffic by vehicle type and road class; distribution of flows by road class; temporal traffic distributions; road length by road type, country and Government Office Region; and road / path area by Government Office Region, stion/roadstatstsc/roadstats08tsc. The full tables of foreign vehicle estimates data for 2008, and all accompanying charts, are also available on the web annex to this publication. Previous published data on foreign vehicle estimates can be found on the DfT website: stion/roadstatstsc/roadstats07tsc. The methodology for the roadside survey which is used to produce the foreign vehicle estimates, can be found on the DfT website: n/. 31

34 Free Flow Vehicle Speeds in Great Britain 4 Free Flow Vehicle Speeds in Great Britain The reduction in overall traffic in 2008 does not appear to have changed average free flow vehicle speeds. In the ten years from 1998, the percentage of vehicles exceeding the 30 mph speed limit on built-up roads has dropped for every vehicle type. The most significant decrease was for cars. In 1998, 69 per cent of cars travelled at speeds in excess of the limit; by 2008 this dropped to less than half (49 per cent). On motorways in 2008, 49 per cent of cars exceeded the 70 mph speed limit. In addition, 15 per cent of cars were recorded as travelling at 80 mph or faster. Very few heavy goods vehicles exceeded their speed limit of 60 mph on motorways. However, over 85 per cent of them exceeded the 50 mph speed limit on dual carriageway non-built-up roads and over threequarters exceeded the 40 mph limit on single carriageway non-built-up roads. In 2008, over half of all motorcycles travelled faster than the 30 mph speed limit in built-up areas. Half of these (or a quarter of the total) exceeded the speed limit by 5 mph or more. On motorways the percentage of cars travelling over 70 mph was at its lowest between 7 and 8 am and 5 and 6 pm. The drop in excessive speed at these times is likely to be due to an increase in traffic volumes during the peak periods. 32

35 Free Flow Vehicle Speeds in Great Britain 4.1 Introduction This section looks at the speed of traffic in free flowing conditions on roads in Great Britain during National administrations in England, Scotland and Wales 5 are responsible for setting speed limits on motorways and trunk A roads. Local authorities have the power to impose or vary speed limits on principal roads and on all other local roads. In order to monitor the compliance of drivers with these speed limits the Department for Transport collects speed data from traffic counting sites around Great Britain. The Department monitors traffic levels at about 180 sites and traffic speeds at about 100 sites using Automatic Traffic Counters (ATC). These are generally situated away from junctions, hills or sharp bends, at locations where traffic is likely to be free flowing and not near speed cameras. Therefore, in principle, they provide information on the speeds at which drivers choose to travel when their behaviour is not constrained by congestion or other road conditions. These statistics do not indicate average traffic speeds across the road network. Any sites affected by long term road works are excluded. Incidents or congested conditions may arise at any site, and when this happens it will reduce speeds below those in free flowing conditions. This is not believed to have a significant effect on the figures published. In this chapter the term built-up is used to describe roads on which a 40 mph or lower limit applies; the term non-built-up describes all other roads. The total number of vehicle records used to produce the 2008 statistics was about 840 million. Since 2002, all vehicles recorded at each ATC site have been included (except for a few very slow moving vehicles indicating that conditions at the site were congested). Table National speed limits on non-built-up roads, Great Britain: 2008 Single carriageways Dual carriageways Miles per hour Motorways Cars and motorcycles Including car-derived vans up to 2 tonnes maximum laden weight Cars or motorcycles towing caravans or trailers Including car-derived vans and motorcycles Buses, coaches and minibuses Not exceeding 12 metres in overall length Goods vehicles Not exceeding 7.5 tonnes maximum laden weight Includes car-derived vans exceeding 2 tonnes maximum laden weight Goods vehicles Exceeding 7.5 tonnes maximum laden weight The Highways Agency for England, Transport Scotland for Scotland and The Welsh Assembly Government for Wales. 33

36 Free Flow Vehicle Speeds in Great Britain 4.2 Non-built-up roads Non-built-up roads: All roads with a speed limit of 50 mph or higher for cars. Free flow vehicle speeds on non-built-up roads, by road type and vehicle type In 2008, the average free flow speed of cars travelling on non-built-up roads was 69 mph on motorways, 67 mph on dual carriageways and 48 mph on single carriageways. Motorcycles had the same average free flow speed as cars on motorways, but were travelling on average 3 mph (at 70 mph) faster than cars on dual carriageways and 5 mph faster than cars (at 53 mph) on single carriageway roads. The average free flow speed of rigid heavy goods vehicles (HGVs) was 59 mph 6 on both motorways and dual carriageways. Articulated HGVs had an average free flow speed of 54 mph 7 on both motorways and dual carriageways. On single carriageway roads, the speed limit for HGVs with three or more axles weighing more than 7.5 tonnes is 40 mph. On these roads the average free flow speed of rigid HGVs in 2008 was 43 mph, 3 mph over the speed limit. This is 5 mph lower than the average free flow speed of cars (48 mph) for which the speed limit is 60 mph. Figure Average free flow speeds on non-built-up roads, Great Britain: Motorways Dual carriageways Single carriageways Average speed (mph) Motorcycles Cars Cars towing Light vans Buses/ coaches 2 axle 3 axle 4 axle 3 or 4 axles 5+ axles Rigid Heavy goods vehicles Articulated Source: National Core Census, Department for Transport 6 Average free flow speed of all rigid heavy goods vehicles. 7 Average free flow speed of all articulated heavy goods vehicles. 34

37 Free Flow Vehicle Speeds in Great Britain On motorways, nearly half (49 per cent) of cars were travelling at a speed that exceeded the 70 mph limit. In addition, 15 per cent of cars were travelling 10 mph or more above the speed limit. On dual carriageways, four in ten cars exceeded the speed limit in On single carriageways, with a 60 mph speed limit, 10 per cent of cars exceeded the limit. Forty eight per cent of motorcycles exceeded the speed limit on motorways, with 52 per cent doing so on dual carriageways. Very few rigid and articulated HGVs exceeded their speed limit of 60 mph on motorways. However, over 85 per cent 8 of them exceeded the 50 mph speed limit on dual carriageway non-built-up roads and over three-quarters (77 per cent) exceeded the 40 mph limit on single carriageway non-built-up roads. Of the HGVs exceeding the speed limit on motorways or dual carriageways, very few were travelling more than 10 mph quicker than the speed limit. However, over a third exceeded the speed limit by 10 mph or more on single carriageway roads. Table Percentage of vehicles exceeding the speed limit on non-built-up roads, Great Britain: 2008 Per cent Motorcycles Cars Cars towing Light vans Heavy goods vehicles Rigid Articulated Buses/ coaches 3 axle 4 axle 3 or 4 axles 5+ axles Motorways by 10 mph or more Dual carriageways n/a by 10 mph or more n/a Single carriageways n/a by 10 mph or more n/a Source: National Core Census, Department for Transport Note: The speed limit for a two-axle HGV and light vans depends on its weight and therefore these data are not presented here or included in the commentary. 8 Average percentage of all HGVs excluding two-axle rigid HGVs. 35

38 Free Flow Vehicle Speeds in Great Britain Free flow car speeds on non-built-up roads, by time of day On motorways, the percentage of cars exceeding the speed limit was greatest between 5 and 6 am (58 per cent) and between 8 and 9 pm (58 per cent). The time periods with the lowest proportions of cars exceeding the speed limit were between 7 and 8 am (37 per cent) and between 5 and 6 pm (39 per cent). The drop in speeds at these times is likely to be due to an increase in traffic volumes during peak periods (see Chapter 3). On dual carriageways, the percentage of cars exceeding the speed limit was greatest in the morning, between 6 and 7 am (42 per cent) and, in the evening, between 7 and 8 pm (44 per cent). On dual carriageways, the percentage of cars exceeding the speed limit did not dip during the morning and evening peak periods as it did on motorways. The percentage of cars exceeding the speed limit on single carriageway roads was higher in the early hours of the morning than it was during the rest of the day. At the maximum, 30 per cent of cars exceeded the limit (between 3 and 4 am). Figure Percentage of cars exceeding the speed limit by time of day on non-built-up roads, Great Britain: 2008 Percentage of cars exceeding the speed limit (hourly average) :00-00:59 01:00-01:59 02:00-02:59 03:00-03:59 04:00-04:59 05:00-05:59 06:00-06:59 07:00-07:59 08:00-08:59 09:00-09:59 10:00-10:59 11:00-11:59 12:00-12:59 13:00-13:59 14:00-14:59 15:00-15:59 16:00-16:59 17:00-17:59 18:00-18:59 19:00-19:59 20:00-20:59 21:00-21:59 22:00-22:59 23:00-23:59 Hour of the day Motorw ays Dual carriagew ays Single carriagew ays Source: National Core Census, Department for Transport 36

39 Free Flow Vehicle Speeds in Great Britain 4.3 Built-up roads Built-up roads: Roads with a maximum speed limit of 40 mph. Free flow vehicle speeds on built-up roads, by road type and vehicle type The average free flow speed of cars in 2008 on 40 mph limit roads was 36 mph and on roads with a 30 mph limit it was 30 mph. These figures are unchanged from The average free flow speed for each vehicle type was within 3 mph of the 30 mph speed limit, with only motorcycles on average travelling faster, at 31 mph, than the legal limit. All types of vehicles averaged the same speed on roads with a 30 mph speed limit in 2008 as they did in Rigid three-axle HGVs and articulated HGVs with five or more axles both averaged 1 mph slower in 2008 than they did in 2007 on 40 mph roads. All other vehicle types travelled at the same average speed on 40 mph limited roads in both 2007 and Figure Average free flow speeds on built-up roads, Great Britain: mph road 40 mph road Average speed (mph) Motorcycles Cars Cars towing Light vans Buses/ coaches 2 axle 3 axle 4 axle 3 or 4 axles 5+ axles Rigid Heavy goods vehicles Articulated Source: National Core Census, Department for Transport 37

40 Free Flow Vehicle Speeds in Great Britain Forty nine per cent of cars exceeded the speed limit on 30 mph roads in 2008, while 18 per cent travelled at 35 mph or more. On 40 mph roads, 24 per cent of cars exceeded the speed limit and 9 per cent exceeded it by 5 mph or more. Motorcycles (53 per cent), light vans (52 per cent) and four-axle rigid HGVs (52 per cent) were the vehicle types that most frequently exceeded the speed limit on 30 mph roads. Twenty seven per cent of buses and coaches exceeded the 30 mph speed limit and 13 per cent exceeded the 40 mph speed limit. Only 7 per cent exceeded the 30 mph speed limit by 5 mph or more and 4 per cent exceeded the 40 mph speed limit by 5 mph or more. Between 43 and 52 per cent of HGVs exceeded the 30 mph speed limit in Seventeen per cent of rigid HGVs with two-axles travelled at speeds of 35 mph or more on 30 mph roads, and 8 per cent at 45 mph or more on 40 mph roads. For all vehicle types, the speed limit was exceeded more on 30 mph roads than on 40 mph roads. Table Percentage of vehicles exceeding the speed limit on built-up roads, Great Britain: 2008 Motorcycles Cars Cars Buses/ Light vans towing coaches Per cent Heavy goods vehicles Rigid Articulated 3 or 4 2 axle 3 axle 4 axle 5+ axles axles 30 mph roads exceeded by 5 mph or more mph roads exceeded by 5 mph or more Source: National Core Census, Department for Transport 38

41 Free Flow Vehicle Speeds in Great Britain Free flow car speeds on built-up roads, by time of day On both 30 mph and 40 mph built-up roads, the percentage of cars exceeding the speed limit was highest in the morning until around 7 to 8 am. The general daily pattern of speeds was similar throughout the day for both 40 mph and 30 mph roads. On 30 mph roads, the percentage of cars exceeding the speed limit was greatest between 5 and 6 am (74 per cent) and was lowest between 8 and 9 am (42 per cent). On 40 mph roads, the percentage of cars exceeding the speed limit was greatest between 3 and 4 am (50 per cent) and was lowest between 11 and 12 pm (19 per cent). Figure Percentage of cars exceeding the speed limit by time of day on built-up roads, Great Britain: 2008 Percentage of cars exceeding the speed limit (hourly average) :00-00:59 01:00-01:59 02:00-02:59 03:00-03:59 04:00-04:59 05:00-05:59 06:00-06:59 07:00-07:59 08:00-08:59 09:00-09:59 10:00-10:59 11:00-11:59 12:00-12:59 13:00-13:59 14:00-14:59 15:00-15:59 16:00-16:59 17:00-17:59 18:00-18:59 19:00-19:59 20:00-20:59 21:00-21:59 22:00-22:59 23:00-23:59 Hour of the day 30 mph roads 40 mph roads Source: National Core Census, Department for Transport 39

42 Free Flow Vehicle Speeds in Great Britain 4.4 Exceeding the speed limit: 1998 to 2008 This section looks at trends in driver behaviour in relation to the speed limit over the last ten years. The percentage of vehicles that exceed the speed limit on 30 mph roads was lower in every vehicle category in 2008 than ten years earlier. In particular the number of cars exceeding the 30 mph speed limit fell from seven in ten in 1998 to less than five in ten in 2008 (as shown in Figure 4.5a). Figure 4.5b shows that around 53 per cent of motorcycles exceeded the speed limit of 30 mph roads in 2008, compared with around 63 per cent in The percentage of motorcycles exceeding the speed limit on 40 mph roads is very similar in 2008 as in 1998 (around 36 per cent). On 30 mph roads, the percentage of two-axle rigid HGVs exceeding the speed limit decreased from 57 per cent in 1998 to 46 per cent in During the same period the proportion that exceeded the speed limit on 40 mph roads increased from 16 per cent to 22 per cent (as shown in Figure 4.5c) From 1998 to 2008 the percentage of articulated HGVs exceeding the 50 mph speed limit on dual carriageways declined from 91 per cent to 86 per cent. Over the same period the number of articulated HGVs exceeding the 40 mph limit on single carriageway non-built up roads increased from 72 per cent to 78 per cent (as shown in Figure 4.5c). Figure 4.5a - Percentage of cars exceeding the speed limit on five road types, Great Britain: 1998 to Percentage of cars exceeding the speed limit mph roads Motorw ays (70) Dual carriagew ays (70) 40 mph roads Single carriagew ays (60) Source: National Core Census, Department for Transport 40

43 Free Flow Vehicle Speeds in Great Britain Figure 4.5b - Percentage of motorcycles exceeding the speed limit on five road types, Great Britain: 1998 to 2008 Percentage of motorcycles exceeding the speed limit mph roads Dual carriagew ays (70) Motorw ays (70) 40 mph roads Single carriagew ays (60) Source: National Core Census, Department for Transport Note: Data for motorcycles exceeding the speed limit do not exist for all years on all road types. Figure 4.5c - Percentage of articulated HGVs exceeding the speed limit on non-built-up roads, and percentage of two-axle rigid HGVs exceeding the speed limit on built-up roads, Great Britain: 1998 to 2008 Percentage of HGVs exceeding the speed limit Dual Carriagew ays (50) (Articulated) Single Carriagew ays (40) (Articulated) 30 mph roads (2 axle) 40 mph roads (2 axle) Motorw ays (60) (Articulated) Source: National Core Census, Department for Transport 41

44 Congestion and Traffic Speeds on the Inter-Urban Road Network in England 5 Congestion and Traffic Speeds on the Inter-Urban Road Network in England On the Strategic Road Network (SRN) in England: The average vehicle delay on the slowest 10% of journeys fell to 3.42 minutes per 10 miles from 3.90 minutes per 10 miles between the baseline year ending March 2008 and the year ending March 2009, a decrease of 12.3 per cent; The average traffic speed over the whole network rose from 55.6 mph in 2005 to 55.9 mph in 2008, an increase of 0.5 per cent. The average speed during the weekday evening peak rose by 0.3 per cent. Average speeds on motorways fell by 0.4 per cent but on dual carriageway A roads they rose by 2.1 per cent. 5.1 Journey time reliability on the Strategic Road Network Trends in journey times and traffic speed can be used as broad measures of congestion, but it is the unreliability of journey times that can cause significant frustration for road users. This section presents information about reliability of journey times on inter-urban roads in England. The Strategic Road Network (SRN) in England consists of all motorways and trunk A roads (dual and single carriageway) managed by the Highways Agency, as well as the M6 Toll. For monitoring purposes, the network has been split into 103 recognisable routes (for example, the A46 from Leicester to Lincoln). Each route is monitored in two directions, so there is a total of 206 route-directions. Currently 95 of the 103 routes are used to monitor network performance due to data quality considerations on the remaining eight routes. Reliability The Department monitors reliability by measuring the average vehicle delay on the slowest 10% of journeys on the SRN (see Box 5.1). This indicator is used to assess performance against the Department's Public Service Agreement (PSA). For the Comprehensive Spending Review 2007 (CSR07), the baseline is the year ending March The measure will be monitored until March 2011, though there is no specific numerical target. The data used for the measure are from the Highways Agency Traffic Information System (HATRIS) database, which brings together journey time and traffic flow data from several different sources. Details of the methodology used for the measure are provided on the DfT website rategicroad

45 Congestion and Traffic Speeds on the Inter-Urban Road Network in England Box Measurement of reliability Average vehicle delay is derived from the differences between observed journey times and a reference journey time (the time that could theoretically be achieved when the traffic is free flowing), weighted by traffic flows for each route of the network. The slowest 10% of journeys are selected for each 15-minute departure time between 6 am and 8 pm for each day of the week, on each of the 95 routes. The indicator therefore reflects journeys experienced on all types of route on all days at all times of the day. Routes consist of a number of links which are sections of road between two junctions. The average journey times for constituent links are aggregated using a process called 'chaining' 10 into a journey time representing that of a vehicle traversing the whole route. Journey time reliability measure for the Strategic Road Network (SRN) Figures 10 for the year ending March 2009 show that average vehicle delay on the slowest 10% of journeys fell to 3.42 minutes per 10 miles from 3.90 minutes per 10 miles in the CSR07 baseline year ending March 2008, a decrease of 12.3 per cent. Provisional figures for the year ending April 2009 show that average vehicle delay on the slowest 10% of journeys fell to 3.41 from 3.90 minutes per 10 miles since the CSR07 baseline year ending March 2008, a decrease of 12.4 per cent. The chart below shows the monthly trend, on a rolling 12 month basis. Figure Journey time reliability measure on the SRN, England: year ending July 2005 to year ending April Delay for slowest 10% journeys (minutes per 10 miles) Baseline to March routes 95 routes Baseline from March Jul 05 Nov 05 Mar 06 Jul 06 Nov 06 Mar 07 Jul 07 Nov 07 Mar 08 Jul 08 Nov 08 Mar 09 Rolling year (month ending) 10 See methodology document. 43

46 Congestion and Traffic Speeds on the Inter-Urban Road Network in England At route level, the average vehicle delay on the slowest 10% of journeys during the year ending March 2009 was highest in the south east around London and in the north west around Manchester, as shown by the routes coloured in orange and red in Figure 5.2. Figure Average vehicle delay per 10 miles for the slowest 10% of journeys on the SRN, England: year ending March 2009 Information derived from the Highways Agency Traffic Information System (HATRIS) database (including data from MIDAS, NTCC and TrafficMaster). Crown Copyright. All rights reserved. Department for Transport [2009] 44

47 Congestion and Traffic Speeds on the Inter-Urban Road Network in England SRN routes with the most delay For the slowest 10% of journeys during the year ending March 2009, on the 95 routes currently being monitored (in each direction): Over 55 per cent of total delay is experienced on only 20 per cent of the routedirections; Twenty per cent of total delay is experienced on the London Orbital road (M25 and A282); The 40 per cent of route-directions with the least delay account for just over 10 per cent of total delay. Routes having the greatest impact on total delay for the slowest 10% of journeys are typically the busiest and longest ones (see Figure 5.4, illustrated by the map in Figure 5.3). Figure Total annual vehicle delay per mile for the slowest 10% of journeys on the SRN, England: year ending March 2009 Information derived from the Highways Agency Traffic Information System (HATRIS) database (including data from MIDAS, NTCC and TrafficMaster). Crown Copyright. All rights reserved. Department for Transport [2009] 45

48 Congestion and Traffic Speeds on the Inter-Urban Road Network in England Figure Total annual vehicle delay on the SRN for the slowest 10% of journeys by route, England: year ending March 2009 Direction as described Opposite direction Route (% change on year ending March 2008) Delay (thousands of vehicle hours) M6 J8 - J20 (-18%) M25 J7 - J16 (0%) M1 J19 - J32 (-11%) M25 J16 - J23 (+10%) M4 J1 - J13 (+6%) M25 J23 - J30 (-27%) M25/A282 J30 - J7 (-33%) M62 J18 - A1 (-16%) M6 M1 - J8 (+21%) M5 M6 - J15 (-21%) M271/M27 Southampton - Portsmouth (-3%) M3 London - Southampton (+9%) M1 J13 - J19 (-10%) A27/A259 Portsmouth - Hastings (-16%) M60 J4 - J18 via Barton (-1%) M6 J20 - J32 (-15%) M5 J15 - J31 (+5%) A1/A1(M) Peterborough - M1 (-18%) A3 London - Portsmouth (+2%) A1/A1(M) Scotch Corner - Newcastle (-13%) M42 J1 - J7 (-6%) M11 J4 - J14 (-7%) A19/A168 Dishforth - A1 N of Newcastle (-8%) A12 M25 - Ipswich (-24%) M40 J1 - J10 (-16%) A1/A1(M) London - Peterborough (-9%) M27/A31/A35 Southampton - Honiton (+3%) M4 J13 - Wales (-18%) M62 J6 - J12 (-10%) A34 M3 - M40 (-12%) M42/A42 M6 Toll - M1 (+9%) M56/A5117 M60 - Wales (-13%) A14 A1 - A11 (-24%) A2 London - M2 J1 (-34%) M60 J18 - J4 via Stockport (-10%) M6/A74 J32 - Scotland (+26%) M40 J10 - M42 (-35%) A38 Birmingham - M1 (-14%) M2/A2 J1 - Folkestone via Dover (+15%) M1 J1 - J6a (+12%) M67/A57/A628/A616 Manchester - M1 (+7%) A50/A500 M1 - M6 (-14%) M20 London - Folkestone (-34%) A303/A30 Amesbury - Exeter (-21%) M62/A63/A1033 A1 - Hull (-8%) A5 M1 J9 - M1 J18 (-18%) A14 M6 - A1 (-10%) A52/A5111/A6 Derby - Grantham (-10%) M1 J32 - J36 (-31%) A38 Exeter - Bodmin (-25%) A21 Sevenoaks - Hastings (+8%) A417/A419 Swindon - Brockworth (-24%) M54/A5 M6 - Wales (-9%) A46 Leicester - Lincoln (-14%) A46 Tewkesbury - Coventry (-19%) A43 M40 - Northampton (-10%) M66/A56 M65 - M62 (-3%) A64 A1 - Scarborough (-10%) A404(M)/A404 M4 - M40 (-20%) A14 A11 - Felixstowe (+12%) M53/A55 Wallasey - Wales (+1%) A5036/M58 Seaforth - M6 (+6%) A23/M23 London - Crawley (-8%) A23 Crawley - Brighton (+2%) A421 M1 - A1 (-2%) A5 M1 J18 - A38 (-20%) M18 M1 - M62 (-51%) A47 Peterborough - Norwich (-8%) A47/A12 Norwich - Lowestoft (0%) A11 A14 - A47 (-4%) M180/A180 M18 - Grimsby (+31%) A453 Kegworth - Nottingham (-4%) A30 Bodmin - Penzance (-57%) M26 M25 - M20 (-34%) A30 Exeter - Bodmin (-14%) M50/A449/A40 M5 - Monmouth (+29%) A303 M3 - Amesbury (-22%) A69 Carlisle - Newcastle (+41%) A66(M)/A66 Darlington - Middlesbrough (+9%) M57 J1 - J7 (+13%) A49 A40 - Shrewsbury (-32%) A13/A1089 Aveley - Tilbury (-34%) M69 M1 - M6 (-19%) A66 Penrith - Scotch Corner (-6%) M1 J42 - J48 (+13%) A556 M6-M56 (-33%) A590 M6 - Barrow-in-Furness (-54%) A595/A66 Sellafield - Penrith (-17%) M55 M6 - Blackpool (-28%) M6 Toll M42 - M6 J11a (-29%) A11 M11 - A14 (+12%) A1 Newcastle - Scottish Border (+35%) A428 A1 - M11 (-73%) M45/A45 M1 - Coventry (-59%) A120 Colchester - Harwich (-42%) 46

49 Congestion and Traffic Speeds on the Inter-Urban Road Network in England Change in average delay since the CSR07 baseline In the 12 months to March 2009 compared with the baseline year, for the slowest 10% of journeys: Average vehicle delay fell to 3.42 from 3.90 minutes per 10 miles, a decrease of 12.3 per cent; Just over 20 per cent of route-directions had at least 1 minute less delay per 10 vehicle miles and almost 8 per cent had at least 2 minutes less delay; Just over 2.5 per cent of route-directions had at least 1 minute more delay per 10 miles; Over three-quarters of the route-directions had less than a 1 minute change in delay per 10 miles. Provisional estimates show that traffic has fallen on the SRN by almost 3 per cent over this period. Recent research suggests there is almost certainly a long term underlying trend for increasing unreliability of journey times caused by increasing traffic levels but the relationship between them is complex. Unreliability is caused by a range of factors including: traffic growth; planned events such as road works and events occurring off the SRN; and unplanned events such as accidents and weather. Each of these factors on their own can lead to changes in reliability, and these changes can be more extreme when the factors work together. Days contributing to total delay In general, large increases and reductions in delay reflect presence or absence of road works in the latest year compared with the baseline period and the effect of severe weather. An analysis of days contributing to delay shows that: In the year ending March 2009, the delays recorded for any one day varied from 8 thousand to 567 thousand vehicle hours. The 36 days with the highest delays accounted for over 25 per cent of all delays; The most significant single contributor to delay since August 2004 was the extreme rainfall on 20 July 2007 which led to flooding of roads and included the closure of part of the M5 and M50. This single day contributed over 886 thousand vehicle hours, equivalent to 2 per cent of the total delays in the baseline year for the SRN; The high winds on 18 January 2007 contributed over 750 thousand vehicle hours delay; The heavy snowfall on 29 October 2008 contributed over 560 thousand vehicle hours delay. 47

50 Congestion and Traffic Speeds on the Inter-Urban Road Network in England Figure Daily contributions to reliability performance on the SRN, England: August 2004 to March Based on 91 routes 18 January High winds Based on 95 routes 20 July Severe flooding on the network Delay (thousands of vehicle hours) October Heavy snowfall Aug 04 1 Feb 05 1 Aug 05 1 Feb 06 1 Aug 06 1 Feb 07 1 Aug 07 1 Feb 08 1 Aug 08 1 Feb 09 Date Average vehicle delay and journey time for slowest 10% and all journeys The slowest 10% of journeys accounted for nearly a third of the total delay experienced on all journeys on the SRN (Table 5.1). Between the CSR07 baseline and the latest year, total delay on all journeys fell by 10.1 per cent compared with a fall of 11.5 per cent for the slowest 10%. Average journey time for all journeys fell by 1.1 per cent compared with 3.5 per cent for the slowest 10% of journeys. Table Average vehicle delay and journey time for slowest 10% and all journeys on the SRN, England: CSR07 baseline and latest year Baseline year Latest year April 07 - March 08 April 08 - March 09 Average delay (minutes per 10 miles) Slowest 10% of journeys All journeys Total delay (million hours) Slowest 10% of journeys All journeys Contribution of slowest 10% (%) Journey time (minutes per 10 miles) Slowest 10% of journeys All journeys Delay as proportion of journey time (%) Slowest 10% of journeys All journeys Absolute change Percentage change 48

51 Congestion and Traffic Speeds on the Inter-Urban Road Network in England For both the slowest 10% and all journeys the greatest decrease in average vehicle delay occurred during the weekday off-peak period and the smallest decrease at weekends. There were also substantial decreases in both the morning and evening peak periods (Table 5.2). Table Average vehicle delay by time of day for slowest 10% and all journeys on the SRN, England: CSR07 baseline and latest year Minutes per 10 vehicle miles / Per cent Weekdays Weekends Week AM peak Off peak PM peak All periods All periods All periods (7am-10am) (10am-4pm) (4pm-7pm) (6am-8pm) (6am-8pm) (6am-8pm) All journeys Baseline Latest Percentage change Slowest 10% journeys Baseline Latest Percentage change Delay by time of day and day of week Average vehicle delay for weekdays during the year ending March 2009: Almost 85 per cent of the total delay on the slowest 10% of journeys occurred during weekdays, and almost half (47 per cent) during the weekday peaks (7 am to 10 am and 4 pm to 7 pm); In general, during the morning peak the average vehicle delay on the slowest 10% of journeys declined as the week progressed. The opposite effect occurred for the evening peak (Figure 5.6); Less than 15 per cent of total delay on a Friday was experienced during the morning peak. On a Monday, 36 per cent of total delay was experienced during the morning peak; Unlike other weekdays, average vehicle delay on Fridays began to increase from 10 am. It continued to rise to an evening peak of 6.94 minutes per 10 vehicle miles at around 4.30 pm. Between 3.30 pm and 5 pm on Fridays, the average vehicle delay was higher than at any other time during the week. 49

52 Congestion and Traffic Speeds on the Inter-Urban Road Network in England Figure Average vehicle delay for the slowest 10% of journeys on the SRN by day of the week and departure time, England: year ending March 2009 Average vehicle delay (minutes per 10 miles) Friday 2 Thursday Tuesday 1 Wednesday Monday 0 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 Departure time Average vehicle delay for weekends during the year ending March 2009: Less than 20 per cent of the delays on the slowest 10% of journeys occurred during the weekends; The delays in the slowest 10% of journeys on Saturdays peaked once during late morning and then tailed off. On Sundays there was a slight peak just before 12 pm and a higher peak just after 5 pm (Figure 5.7). Figure Average vehicle delay for the slowest 10% of journeys on the SRN by day of the weekend and departure time, England: year ending March Average vehicle delay (minutes per 10 miles) :00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 Departure time Sunday Saturday 50

53 Congestion and Traffic Speeds on the Inter-Urban Road Network in England Delay on public holidays by time of day Public holidays are not included in the journey time reliability measure. Public holidays include bank holidays and Christmas Day. When Christmas Day, Boxing Day, or New Year s Day occur on a weekend, these days and the following Monday (and if applicable Tuesday) are all considered public holidays. Christmas Days contribute very little delay and follow no real trend, and have therefore been excluded from the following analyses. This section looks at average vehicle delay for all journeys, and is based on 90 out of 103 routes which make up the SRN to provide a consistent set of routes for 2006 to Average delay on public holidays followed similar trends between 2006 and 2008 with a peak around am to 12 pm. The peak for 2007 was slightly higher than in other years (Figure 5.8). Average delay on public holidays in 2008 in the late morning peak, around am to 12 pm, was 1.03 minutes per 10 vehicle miles. Figure Average delay for all journeys on public holidays on the SRN, England: 2006 to Average vehicle delay for all journeys (minutes per 10 miles) :00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 Departure time

54 Congestion and Traffic Speeds on the Inter-Urban Road Network in England In 2008, average delay on public holidays followed a trend more similar to Saturdays than on Sundays, with a morning peak at around am. However, between 3.30 pm and 5 pm average vehicle delay was on average approximately 70 per cent higher on public holidays than on Saturdays (Figure 5.9). Figure Average delay for all journeys on public holidays, Saturdays and Sundays on the SRN, England: Average vehicle delay for all journeys (minutes per 10 miles) Public 0.2 holidays Saturdays :00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 Departure time Sundays 52

55 Congestion and Traffic Speeds on the Inter-Urban Road Network in England 5.2 Traffic speeds on the Strategic Road Network This section presents data on speeds derived from the HATRIS database. The data are presented for 2005 to 2008 and are on the same basis as the journey time reliability measure in that they relate to 15-minute departure times between 6 am and 8 pm for each day of the week. However, to enable comparisons over the period 2005 to 2008 they are based on 90 routes (i.e. 180 route-directions). Also, the speed data cover all journeys, not just the slowest 10%, and are calculated on a link basis, rather than being chained, to enable disaggregation by road types. The number of links on each route-direction varies between two and 35 and is on average about ten. Links for which data of adequate quality is not available for all four years have been removed from the analysis. Speeds in this section are representative of all types of traffic conditions, whereas vehicle speeds in Chapter 4 are recorded only in free flowing conditions. Speeds on the SRN: 2005 to 2008 The average traffic speed on the SRN between 6 am and 8 pm rose from 55.6 mph in 2005 to 55.9 mph in 2008, a rise of 0.5 per cent. This followed a fall in speed of 0.8 per cent between 2005 and 2006 and little change between 2006 and 2007 (Table 5.3). There were similar rises between 2005 and 2008 during the weekday peak and off-peak periods. The largest rise was 0.9 per cent during the weekday off-peak periods. The average speed on motorways fell by 0.4 per cent from 59.3 mph in 2005 to 59.0 mph in Between 2005 and 2008, the average speed on all trunk A roads rose by 1.9 per cent from 50.0 mph to 50.9 mph. On single carriageway A roads, the average speed rose from 44.9 mph to 45.5 mph. On dual carriageway A roads there was a larger increase in the average speed of 2.1 per cent to 53.4 mph. 53

56 Congestion and Traffic Speeds on the Inter-Urban Road Network in England Table Average traffic speeds on the SRN by time period and road type, England: 2005 to 2008 Miles per hour/per cent Change Absolute change % Time period Weekdays AM peak (7am-10am) Off-peak (10am-4pm) PM peak (4pm-7pm) All Weekdays (6am-8pm) All Weekend (6am-8pm) All Week (Mon-Sun, 6am-8pm) Road type Trunk 'A' roads dual carriageway single carriageway All trunk 'A' roads Motorways Strategic Road Network Network speeds as a proportion of road length On average during weekdays in 2008 the average speed on half of the motorway network was over 60 mph. On nine-tenths of the motorway network the speed was over 50 mph (Table 5.4). On dual carriageway A roads, the average speed on weekdays was over 50 mph on just under three-quarters of the road length in On single carriageway A roads, the average speed on weekdays was over 40 mph on just under four-fifths of the road length, and over 50 mph on a quarter of the road length. Table Traffic exceeding a given speed by proportion of road length on the SRN, England: 2008 Percentage of total road length Weekdays Weekend All week AM peak Off-peak PM peak All day All day All day 7am-10am 10am-4pm 4pm-7pm 6am-8pm 6am-8pm 6am-8pm Motorways over 30 mph over 40 mph over 50 mph over 60 mph over 70 mph Dual carriageway 'A' roads over 30 mph over 40 mph over 50 mph over 60 mph over 70 mph Single carriageway 'A' roads over 30 mph over 40 mph over 50 mph over 60 mph over 70 mph

57 Congestion and Traffic Speeds on the Inter-Urban Road Network in England Traffic speeds as a proportion of vehicle kilometres On weekdays in 2008, 87 per cent of traffic on motorways travelled at an average speed of over 50 mph. Forty six per cent travelled at 60 mph or more (Figure 5.10). On dual carriageway A roads, 74 per cent of traffic travelled at an average speed of more than 50 mph. Seven per cent travelled at an average speed of less than 40 mph. On single carriageway A roads, the average speed on weekdays in 2008 was greater than 50 mph for 36 per cent of all traffic, and greater than 40 mph for just over 80 per cent of traffic. Figure Distribution of average speeds by road type on weekdays on the SRN, England: Motorway Dual carriageway A road Single carriageway A road Proportion of vehicle kilometres (%) >70 Speed (mph) 55

58 Congestion in English Urban Areas 6 Congestion in English Urban Areas In the ten largest urban areas in England: The average person journey time in was 4 minutes 8 seconds per mile. This was 1 second per mile faster than , and 8 seconds per mile (3.1 per cent) faster when compared to the baseline; Average morning peak speeds on key routes in the ten largest urban areas vary considerably, both geographically and on a day to day basis. Thirteen per cent of monitored route segments achieve average speeds of 26 mph or faster, and 41 per cent have average speeds of 15 mph or slower; The morning peak in congestion on the key routes is slightly less pronounced on Fridays than other days in the week. There is little or no morning peak on these routes on weekends or during school holidays. This chapter looks at congestion in the ten largest urban areas in England, which together make up the Department s urban congestion Public Service Agreement (PSA) indicator. This publication examines in more detail speeds and variability on the individual route segments that make up the urban congestion PSA indicator, and variation in speeds by time of day, day of week and during the school holidays. Data on trends in congestion in the ten largest urban areas are available in Road Traffic and Congestion in Great Britain: Quarter Box Measures of urban congestion The Department tracks progress towards the urban congestion target using average person journey time per mile. This is the average time it takes a person to travel one mile. This includes people travelling on stopping buses as well as non-stopping vehicles (cars, light vans, heavy goods vehicles (HGVs), minibuses and coaches). It takes account of the number of people in each vehicle, as well as the number of vehicles, with the extra data being collected through local surveys. The data are derived from location reports taken from in-vehicle Global Positioning System (GPS) devices. Congestion measures are based on the weekday morning peak, excluding school holidays, when congestion is highest. The peak times used vary between urban areas, some using 7 am to 10 am and others 7.30 am to 9.30 am. The indicator is based on a selection of target routes (mainly principal roads) agreed with local authorities. These key corridors are important to the functioning of the urban area. Most routes are inbound towards urban centres, although some are orbital routes, and a few (including all routes in London) are monitored in both directions. The later analyses presented in this chapter are based on average journey time per mile. This is a similar indicator to the person based measure, but excludes the local survey data. This means it can be used for a broader range of analyses. 11 Available at: 56

59 Congestion in English Urban Areas 6.1 Congestion in major urban areas in England Table 6.1 shows the person journey times for the baseline 12 and the academic years and , together with the percentage change since the baseline. The table also shows the percentage change in person miles, the total distance travelled by people on the target routes. Percentage changes in individual urban areas of less than 2 per cent are unlikely to be statistically significant, and so may not be indicative of real changes in congestion. Across the ten urban areas, the average person journey time in was 4 minutes 8 seconds per mile. This was 1 second per mile faster than , and 8 seconds per mile (3.1 per cent) faster when compared to the baseline. Five out of the ten urban areas have experienced a decrease in congestion of 2 per cent of more, as measured by person journey times. None of the areas experienced a rise in congestion of more than 2 per cent. In aggregate, the number of person miles travelled decreased by 2.7 per cent since the baseline. Table Person journey times and travel during the morning peak, ten largest urban areas: Baseline, and minutes and seconds per mile Percentage change since baseline Person journey time Person journey Baseline time Person miles London 4:21 4:12 4: Greater Manchester 5:00 4:51 4: Merseyside 4:07 3:56 4: South Yorkshire 4:14 4:01 4: Tyne & Wear 3:20 3:17 3: West Midlands 3:54 3:46 3: West Yorkshire 4:03 4:07 4: Bristol 3:57 3:56 3: Leicester 4:21 4:18 4: Nottingham 3:48 3:52 3: All areas 4:16 4:09 4: The baseline uses data from both and

60 Congestion in English Urban Areas 6.2 Journey speeds and variability by area The maps in this section examine journey speeds and variability of non-stopping vehicles on each of the route segments that make up the urban congestion PSA indicator. Maps of three of the areas are presented in this chapter as examples, with maps of all ten areas available in the web annex to this publication 13, during the weekday morning peak, for the year September 2007 to August Journey speeds are measured in miles per hour. Due to changes in methodology and the data supplier, the speeds presented in this analysis are not directly comparable with those that featured in Road Statistics 2007:Traffic, Speeds and Congestion. Variability is a measure of day to day variation in average speed along a specific route segment. Segments have been assigned to low, medium and high variability bands of equal sizes. In this way, the variability of any given route segment is relative to the other monitored route segments across the ten large urban areas. Comparisons between different urban areas should be made with caution. Speed and variability are influenced by a number of factors, including the nature of the routes being monitored, prevailing traffic levels and road conditions such as road works. Table 6.2 below summarises the percentage of segments monitored in each urban area falling into each speed and variability band. Table Percentage and number of target route segments by urban area, speed band and variability band during morning peak, ten largest urban areas: year ending August 2008 By average speed band Over 25 mph mph mph Percentage / Number of segments By variability band Low Medium High Total included segments * London Greater Manchester Merseyside South Yorkshire Tyne & Wear West Midlands West Yorkshire Bristol Leicester Nottingham All areas * A small number of route segments were excluded because of insufficient data coverage for the variability analysis: 2 in Greater Manchester, 1 in London, 1 in Nottingham, 3 in South Yorkshire and 1 in West Yorkshire

61 Congestion in English Urban Areas Table 6.2 shows that 41 per cent of monitored route segments experience average speeds of 15 mph or slower during the morning peak. Thirteen per cent of route segments experience average speeds of 26 mph or faster. Bristol and Tyne & Wear both have relatively high proportions of faster moving route segments, while London and Greater Manchester have the highest proportions of slow moving segments. South Yorkshire has the highest proportion of route segments with high variability, while London and the West Midlands have the highest proportion of low variability segments. Developing the speed / variability map West Midlands case study The following three figures show how maps of speed and variability are combined to produce a single map showing how speed and variability change along segments of target routes. This example shows the West Midlands. Combined speed / variability maps of Tyne & Wear and Leicester are also presented in this publication. These areas have been selected so as to demonstrate this analysis for urban areas of different sizes. Maps for all ten urban areas are available in the web annex. Figure 6.1 shows the average daily speed of non-stopping vehicles on route segments monitored under the urban congestion PSA indicator for the West Midlands (for data based on the year ending August 2008). Average speeds have been calculated for the morning peak period (7 am to 10 am in the West Midlands) on weekdays during school term time. Figure Average speed of non-stopping traffic on target routes, West Midlands: year ending August

62 Congestion in English Urban Areas Fifty four per cent of route segments in the West Midlands have traffic flowing along them at an average speed of 16 to 25 mph. Traffic tends to slow approaching city centres, for example the northern section of the A461 into Walsall and the southern section of the A34 into Birmingham. However not all routes follow this pattern; the A38 into Birmingham from the east is fastest on the segment closest to the city centre. Note that eight route segments (none of which were in the West Midlands) were excluded from these analyses because there was insufficient data to calculate reliable measures of speed and variability. The speed at which traffic flows along these routes only tells one part of the story; the average speed map does not show how much these speeds vary on a day to day basis. Figure 6.2 illustrates how variable the average route segment speeds are in the West Midlands. Each route segment has been designated as low, medium or high variability. Low variability denotes a stretch of road where journey times are relatively predictable, and drivers will have a good idea how fast traffic moves on a daily basis. High variability segments are those where traffic speed changes more from day to day. Figure Speed variability of non-stopping traffic on target routes, West Midlands: year ending August

63 Congestion in English Urban Areas It can be seen from Figure 6.2 that a number of the routes are more variable near Birmingham city centre (with the innermost segments of the A34 south of Birmingham and the A45 and A38 to the east all falling into the highest variability band). The A34 north of Birmingham is an example of a more reliable route, with none if its segments falling into the high variability band. Overall, 52 per cent of all route segments in the West Midlands fall into the low variability group. Figure 6.3 below combines the average speed and variability analyses together. The information about speed and variability can still be read from the map, but it is also possible to combine the two measures to get a broader picture of traffic conditions. Figure Average speed and variability of non-stopping traffic on target routes, West Midlands: year ending August 2008 For example, the westbound A45 towards Birmingham city centre is fastest (over 25 mph) on the outskirts of the city. As you move closer to the centre, traffic slows to between 16 and 25 mph, but the variability of this journey speed is higher; motorists are less likely to experience much faster or slower speeds. Traffic on the innermost segment of the route still runs at between 16 and 25 mph on average, but the day to day variability is much greater. In contrast, journey speeds along each segment of the A38 east of Birmingham city centre are relatively unreliable. However, the route overall is quite quick in relation to the rest of the West Midlands, with average journey speeds faster than 25 mph on average near the city centre. 61

64 Congestion in English Urban Areas Maps of speed and variability further examples Two further example combined speed and variability maps are now presented, for Tyne & Wear and Leicester. Figure Average speed and variability of non-stopping traffic on target routes, Tyne & Wear: year ending August 2008 Figure 6.4 illustrates the average speed and day to day variability of the target routes in Tyne & Wear. The segments furthest from the major urban centres are the fastest moving parts of the routes. These routes slow to an average speed of 16 to 25 mph at the urban centres in most cases. The slowest segments in the Tyne & Wear area are on routes inbound to Newcastle and Gateshead centres; the routes into Sunderland are relatively uncongested. There is no distinct pattern of variability across all routes. For example, the A1018 from Sunderland to South Shields is a reliable route with an average speed in excess of 15 mph. The A1058 however is a more variable route, with traffic slowing to less than 15 mph as it approaches Newcastle city centre. Note that there was not sufficient data to calculate average speed and variability for one segment of the A167, and it has been excluded from this analysis accordingly. 62

65 Congestion in English Urban Areas Figure Average speed and variability of non-stopping traffic on target routes, Leicester: year ending August 2008 Figure 6.5 above shows that in Leicester there are a high proportion of route segments with slower speeds. Ninety seven per cent of the route segments have an average speed of 25 mph or less, and almost half are 15 mph or slower. This may be in part because Leicester monitor a shorter morning peak period (7.30 to 9.30 am) than most urban areas. The fastest flowing parts of the Leicester network can be found on the A50 and A5460. Journey speeds in Leicester are generally more variable than in other urban areas, with 83 per cent of route segments in Leicester falling in the medium and high variability bands. Many routes into Leicester become more reliable as they get closer to the city centre, particularly from the south and west, although journey speeds still tend to slow to 15 mph or slower. However, every segment of the A6 approaching Leicester from the north is in the highest variability band, and speeds along the A594 inner ring road and A47 east of the city centre are similarly unreliable. 63