ESTABLISHING A NATIONAL SYSTEM FOR MONITORING SAFETY PERFORMANCE INDICATORS IN ISRAEL; AN EXAMPLE OF A NATIONAL SPEED SURVEY

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1 Међународна Конференција Индикатори перформанси безбедности саобраћаја Србија, Београд, Хотел М, 6. март International Conference Transport Safety Performance Indicators Serbia, Belgrade, Hotel M, March 6, ESTABLISHING A NATIONAL SYSTEM FOR MONITORING SAFETY PERFORMANCE INDICATORS IN ISRAEL; AN EXAMPLE OF A NATIONAL SPEED SURVEY Victoria Gitelman 1 Abstract: Safety performance indicators (SPIs) reflect those operational conditions of the road traffic system which influence the system s safety performance. Recognizing the great potential of the SPIs for road safety management and being encouraged by recent developments in Europe, a national system for producing and monitoring SPIs was established in Israel. The system covers six safety areas: speeding; use of safety belts; use of child restraints in cars; bicycle helmet wearing; pedestrian behaviour at crosswalks and alcohol-impaired driving. In each area, the data are collected by means of a national observational survey; most surveys run annually, since For each survey, the framework for data collection and assessing SPIs was developed based on a review of the international experience on the subject and having defined sampling rules for producing nationally representative SPIs. Furthermore, methods for estimating SPI values and their confidence intervals were suggested as well as for monitoring their over-time changes. As an example, the paper presents speed SPIs estimated for the Israeli road network in All rural road types are associated with a significant share of non-compliance with speed limits, where the highest level of non-compliance (60%-70%) was observed on dual-carriageway roads with atgrade junctions and on single-carriageway roads. In urban areas, the major speeding problem is associated with dual-carriageway collector streets situated in city centers. The examination of changes in speed SPIs over-time demonstrated no essential changes in 2012 versus 2011, in spite of the automatic speed enforcement program that was launched in the country in Keywords: safety performance indicators, national observational surveys, monitoring, speeds. 1 Prof Victoria Gitelman, Ph.D., Senior Research Fellow, Deputy director of the Ran Naor Road Safety Research Center, Technion - Israel Institute of Technology, Technion City, Haifa, Israel; trivica@technion.ac.il 27

2 1. INTRODUCTION Current approaches towards improvements in road safety are based on the systematic measurement and evaluation of the road safety situation. It is generally accepted that national safety plans and targets need to be monitored periodically, to verify the progress made and to adopt necessary changes based on recent trends observed (OECD/ITF, 2008; OECD/ITF, 2013). Similarly, estimating the impact of various safety interventions, a recommended practice today is to consider changes in relevant accidents and/or safety-related behaviours (Elvik et al, 2009). When monitoring the progress, in the past, road safety was usually assessed in terms of accidents, injuries or their social costs. However, as it was recognized more than a decade ago (ETSC, 2001), counting accidents or injuries only does not offer sufficient insight into the factors that affect safety, including those that can be controlled for, and thus, safety performance indicators are required to provide a means for monitoring the effectiveness of safety actions applied. The place of safety performance indicators (SPIs) in a safety management system was originally described in a New Zealand Land Traffic Safety Authority paper (LTSA, 2000) and then in a report written by a group of European road safety experts (ETSC, 2001). Later on, the European Commission funded the SafetyNet project which provided further methodological fundamentals for SPI development, in a number of road safety areas (Hakkert et al, 2007). The place of SPIs in a safety management system is shown in Figure 1. The model presents essential elements of a safety management system in the form of a road safety pyramid defining a number of layers such as: safety interventions (measures and programs), outputs from implementation of certain measures and safety performance indicators (as intermediate outcomes), the numbers of accident fatalities/injuries (as final outcomes), and the social costs of accidents/injuries. To note, further developments of the road safety pyramid can be found, e.g., in Wegman et al (2008), Bliss and Breen (2009), where more emphases are given to background characteristics of the countries compared (structure and culture layer), as well as to road safety policy context, structure and performance. A core issue in the development of SPIs within the SafetyNet project was that they should be able to reflect unsafe operational conditions of the road traffic system and should therefore be of a more general nature than direct outputs of specific safety interventions. In order to demonstrate a more general character of SPIs and their independence from interventions, the layer of 'intermediate outcomes' was divided into 'operational conditions of the road traffic system' and 'outputs' (from measures/ interventions). Consequently, the definition of SPIs suggested by SafetyNet was as follows (Hakkert et al, 2007): safety performance indicators are the measures (indicators), reflecting those operational conditions of the road traffic system, which influence the system s safety performance. The SPIs' purpose is: to reflect the current safety conditions of a road traffic system; to measure the influence of various safety interventions; to compare between different road traffic systems, e.g. countries, regions, etc (all those not in the context of a specific safety measure, but in the context of specific safety problems or safety gaps). In general, a large number of potential safety performance indicators is possible (ETSC, 2001). However, not all of them are equally important. The importance of a safety performance indicator can be assessed in terms of the strength of its relationship 28

3 with accident or injury occurrence, whether it makes a major contribution to accidents and whether it can be influenced by road safety measures. A natural starting point would be the main behavioural indicators: speeding, drink-driving and seat-belt use. Thereafter, quality indicators concerning other components of the road traffic system such as road networks and vehicle fleets should be added as well as the post-crash treatment of road accident victims. Thus, within the SafetyNet project, SPIs were developed for seven problem areas which are: alcohol and drugs; speed; (use of) protective systems; (use of) daytime running lights; vehicles (passive safety); roads; trauma management. Figure 1. Place of SPIs in safety management system (Hakkert and Gitelman, 2007) For each of these areas, SPIs were developed using a common development procedure as follows (Hakkert et al, 2007). First, based on a literature survey, a relationship between the problem area and road safety was defined, and the scope of the accident/ injury reduction potential associated with better system's operational conditions (e.g. lower speeding, better passive vehicle safety) was stated. Second, characteristics of the system's performance, user behaviour, etc were analyzed in order to select those of them which can be measured and quantified. Using a literature survey, examples of SPIs in use by different bodies (countries, authorities) and/ or research studies, were considered. Third, the SPI concept in a specific problem area was developed, which stems from the structure of the area considered, the available experiences with measurements of similar characteristics, etc. Once the SPIs were defined, the data for estimating SPIs were collected via national experts enabling various country comparisons (e.g. Vis and Eksler, 2008). Moreover, recognizing that a prerequisite for using SPIs for monitoring and comparisons lies in sufficient data quality while the data should also be collected in a harmonised fashion, an SPI Manual was developed (Hakkert and Gitelman, 2007). The Manual demonstrated existing practices for the underlying data measurements, provided good practice examples (when available), and detailed the procedures which are necessary to collect and process the required data for the estimation of the SPIs' set on a national level. 29

4 A literature survey demonstrated (Hakkert et al, 2007) that a number of European countries such as Finland, France, Sweden, Hungary, Switzerland, the Netherlands, the UK, have been carrying out systematic national behaviour surveys on selected road safety behaviours since the 1990s or even earlier. Repeated measurements are performed on a regular basis, which enables the assessment of traffic behaviour trends and of the impacts of countermeasures applied and/or the advance of safety programmes. The most frequently covered areas in such surveys are speeds, drinking and driving and the use of vehicle restraint systems. On the other hand, since the mid 2000s there was a growing interest of international bodies in the use of safety performance indicators for country comparisons. For example, the European Transport Safety Council (ETSC) initiated the Road Safety Performance Index project promoting the country comparisons in terms of safe road user behavious, road infrastructure and vehicles, beside various analyses of crash injury data (e.g. Jost et al, 2009; ETSC, 2010). Similarly, the IRTAD group supported country comparisons as to the use of seat-belts in cars, helmets' use by motorcyclists, travel speeds, together with other safety management issues (e.g. OECD/ITF, 2008). Recognizing the great potential of the SPIs for road safety management and being encouraged by recent developments in Europe, a national system for producing and monitoring SPIs was established in Israel. The system was commissioned by the National Road Safety Authority (NRSA) and devoted to the development of behavioural SPIs (Israel, 2008). The areas for measuring road user behaviours were selected based on the international practice (as to the importance of the topic for improving road safety) and also accounting for the urgent road safety issues, for the country. In each area, the SPIs developed were intended to provide a representative sample of such behaviours for national indices and to serve for setting and monitoring road safety targets (Israel, 2008). The system covers six safety areas: speeding; use of safety belts; use of child restraints in cars; bicycle helmet wearing; pedestrian behaviour at crosswalks; alcohol-impaired driving. In each area, the data are collected by means of a national observational survey, where in most areas, the surveys run annually, since This paper describes the methodology applied for establishing the national system for monitoring behavioural SPIs in Israel. As an example of the system's product, the paper details speed SPIs estimated for the Israeli road network in METHODOLOGY FOR ESTABLISHING THE NATIONAL SYSTEM FOR MONITORING BEHAVIOURAL SPIS The development of a framework for data collection and assessing road safety behaviour SPIs in Israel relied on the principles suggested by the SPI Manual (Hakkert and Gitelman, 2007). For each survey, the framework developed was based on a review of international experience on the subject, aiming, on the one hand, to demonstrate the relevance of the issue selected for improving road safety in the country and, on the other 30

5 hand, to examine the main characteristics and components of similar surveys carried out in other countries. Setting up a survey, the issues to be dealt with concerned: a definition of the survey population, SPIs to be estimated, method of data collection (survey instrument), sampling unit and sampling design, for producing nationally representative SPIs Speeds Speed is one of the main contributors to road accidents having a direct influence on their severity (OECD, 2006). According to different estimates (e.g. TRB, 1998; OECD, 2006), speed is a major contributory factor in around 10% of all accidents and in about 30% of fatal ones. Due to the massive character of speeding and inappropriate speeds, managing drivers speeds has a high safety potential (OECD, 2006). The relation between speed and accidents is abundantly studied in the literature. For example, Aarts & Van Schagen (2006) concluded that the safety effect of a particular change in speed depends on the type and, thus, characteristics of the road. They estimated from the studies reviewed that an average speed change of 1 km/h leads, depending on road type, to 2%-4% change in injury accidents and to 3%-8% change in fatal accidents. Thus, speed SPIs can be a useful tool for various road safety purposes, e.g. monitoring performance of the road network; evaluation of the effectiveness of anti-speeding measures; estimation of impact of the police enforcement, etc. The speeds that were found as most relevant for road safety purposes were spot speeds measured at various locations on the road network during periods when traffic can be considered free-flowing (Hakkert et al, 2007). Since traffic populations and traffic circumstances differ among road type, time of day (day vs. night), day of week (weekdays vs. weekend), it is necessary to have different speed SPIs for different road types and different reference time periods. Speeds are systematically monitored in a number of European countries. Mostly, three types of devices are applied for collecting spot speed data: hand-held, in-road and out-of-road devices. An overview of the main devices' characteristics can be found in Riguelle et al (2007). As indicated, the use of hand-held devices (radar and laser guns) is more efficient on less-trafficked roads, whereas other devices are more suitable for highly-trafficked roads. For example, in Finland, a speed survey belongs to the Traffic Behaviour Monitoring System that was established in 1992 (Luukkanen, 2003). The data are collected by means of in-road devices distributed throughout the rural road network, where speed indicators (mean speeds, the percentage of drivers exceeding the speed limit) are produced for two main road types, with 100 and 80 kph speed limits. In Sweden, a speed survey takes place since 1996, where speed measurements are performed by means of on-road traffic counters, on five types of non-urban (state) roads and three types of urban roads (Isaksson, 2003). In France, speed measurements are carried out by means of a radar gun, on 362 road sections, representing eight road types (Riguelle et al, 2007). In Ireland, a bi-annual speed survey takes place since 1999, covering 88 sites on six nonurban and four urban road types, where the measurements are performed in pre-defined hours, by means of a radar gun (NRA, 2005). In the UK, the annual speed survey is based on the data collected from 96 automatic in-road counters, representing five road types (Vehicle speeds, 2006). 31

6 The purpose of the speed survey in Israel is to characterize free-flow vehicle speeds on the national road network. In line with the SPI Manual, the speed SPIs suggested for application in Israel were the mean speed, the 85th percentile of speed, percentage of vehicles over the speed limit and percentage of vehicles travelling at high speeds (plus 20 kph over the speed limit, e.g. over 130 kph on motorways, over 70 kph on urban streets), during day and night hours, on typical working days. The sampling units of the survey are traffic lanes on the road sections that were randomly selected on the road network for the pre-defined road types; furthermore, a measurement site selected on each section satisfies the definition of free-flow conditions (see Riguelle et al, 2007). In accordance with the main road types of the existing road network, the Israeli speed survey covers eight road types, including five rural and three urban road types as detailed in Table 1. The speed measurements are performed by means of pneumatic traffic counters, on all types of rural roads and on arterial urban roads, and by means of speed guns, on urban streets. The traffic counters are left on a site for 24 hours; aiming to consider free-flowing vehicle conditions only, hours with more than 800 vehicles per hour per lane are excluded from the analysis. Using a speed gun, only "first in line" or a single-going vehicle is selected for measurements, collecting per site 100 measurements of vehicles in day-hours (10-15) and 100 in night-hours (22-6). Table 1. The number of sites, per road type, in Israeli speed survey Road type Speed limit, kph Number of sites Rural (non-urban) roads 75 Motorways (right lane) + 5 (left lane) Dual-carriageway roads without at-grade (right lane) + 5 (left lane) junctions Other dual-carriageway roads (with atgrade junctions) (right lane) + 15 (left lane) Single-carriageway roads Local roads Urban roads 60 Arterial roads 70 6 (right lane) + 12 (left lane) Central collector streets (dualcarriageway) Residential collector streets (singlecarriageway) Considering the number of sites required for the survey, a rule of minimum five sites per lane type was applied. For rural roads, the number of sites was defined having examined the length and the traffic volume subdivision between the road types, while selecting the sites for the survey, the geographic distribution of roads was also accounted for. For urban roads, a stratified sample was applied for sample design, with two characteristics considered: size and geographic area of a town, where population size served as a substitute for traffic exposure. The strata were defined separately for each road type, in accordance with the availability of various towns and road types, in different geographic area. For example, for arterial roads, four strata were defined according to large or "other" towns, situated in the center or "other" areas of the country, where for other urban road types, seven strata were defined, with three town sizes and three geographic areas involved. For each stratum, weights are estimated based on the 32

7 country population distribution in the year closest to the year of survey, which are then applied for evaluating nationally representative SPIs. In total, the survey includes 135 sites distributed throughout the country. Figure 2 illustrates, as an example, a geographic distribution of sites selected for the speed survey on rural roads. The speed measurements are conducted in June, annually, since The speed SPIs are estimated per site and then are weighted for each road type, in day and night hours. In addition, for each road type (not per site) speed SPIs are produced for separate vehicle types: light vehicles, trucks and heavy good vehicles (with total weight over 4 ton), buses and motorized two-wheelers. North Center South Legend: Speed survey sites on Motorways Dual-carriageway roads without atgrade junctions Other dual-carriageway roads Single-carriageway roads Local roads Figure 2. Geographic distribution of speed survey sites on rural roads 33

8 2.2. Use of safety belts The use of seatbelts is one of the most effective means of reducing fatal and non-fatal injuries in motor vehicle crashes. It diminishs the death rate of car occupants by at least 40% (ETSC, 2001). Nowadays, the use of seat belts is mandatory in all developed countries, but the law continues to be violated by a certain proportion of traffic participants. Using a method developed in the US (Glassbrenner, 2003) it was demonstrated (ETSC, 2010) that in one year in the European Union (EU), thanks to the use of safety belts, 12,400 lives of car occupants were saved where additional 2,500 lives would be saved if the level of seat-belt use were 99%. In the international practice there is a consensus concerning the importance of seatbelt use monitoring for promoting road safety in a country (OECD/ITF, 2008; ETSC, 2010). The use of seatbelts has regularly been assessed in several European countries (e.g. Switzerland, France, Germany, UK, Finland, Sweden), starting from the introduction of seatbelt-related regulations, several decades ago. According to common practice, in this domain, direct SPIs are applied which are the rates of safety belt use by various car occupants: drivers, passengers on the front seats, passengers on the rear seats, in the day-time hours (Hakkert and Gitelman, 2007). The most common method used to collect the data are by means of visual observations performed by trained observers who are placed on the roadsides of sites of natural vehicle stops (e.g. signalized intersections). In several European countries, the seatbelt SPIs are estimated by means of a national observation survey, in which the measurements are classified according to main road types and population areas (see examples in Luukkanen, 2003; Broughton, 2003; Hakkert and Gitelman, 2007). The values for major road types and population groups are then aggregated into one indicator (of each type) for the country. The amount of sites required for the survey and the number of observations per site depend on the statistical reasons (accuracy/sampling error and confidence level required - see Chapter 2 in the SPI Manual) and cost/logistic considerations of the survey. For example, the seatbelt surveys in such countries as UK, Ireland, Switzerland, Finland and South Dakota in the US, comprise between measurement sites, where the number of vehicles observed in a survey ranges between thousands. Based on the SPI Manual and international experience, a similar framework was developed for estimating seatbelt SPIs in Israel. For survey design, a stratified sample was applied, in two stages: (1) an initial stratification according to urban/rural areas, based on a relevant subdivision of traffic exposure (vehicle-km traveled); (2) further stratification using additional characteristics such as: (a) road type and geographic region, for rural area; (b) town type, for urban area. Table 2,a illustrates the structure of the national seatbelt survey in Israel - the strata defined, together with the weights of each component estimated for the first national survey. Table 2,b demonstrates the amount of sites assigned to each stratum. The latter was based on the requirement for estimation accuracy of the SPIs evaluated by the survey (e.g. 2%-3% accuracy with 95% confidence interval) and on the assumption on the number of observations collected per each site. Thus, the survey is carried out at 70 sites distributed throughout the country, including 35 sites on rural roads and 35 sites on urban roads, where the observation sites are selected according to the pre-defined types of rural roads (motorway, dual-carriageway, single-carriageway) and according to three 34

9 types of towns (Jewish, mixed-population, Arab), while preserving the geographical spread. The sample units of the survey were road intersections (mostly, signalized ones but also some non-signalized for single-carriageway roads and interchange ramps for motorways), which were randomly selected for each stratum. The survey is conducted on working days, between 7-19 hours. At each site, the observations continue four hours, aiming to collect a sample of 500 vehicles observed (light vehicles only). The data collected concern the place of seating of each car occupant, the use of safety belts, gender and age group. Table 2. Structure of the national seatbelt survey in Israel a) Weights of the strata defined (for 2009 survey) Strata 2a: Region** 1: Area type* South and Jerusalem Road type* North Centre Total Rural: 0.60 Motorways Dual-carriageway roads Others Total b: Town type** Mixedpopulation Jewish Arab Total Urban Arterial or collector : 0.40 roads * According to exposure subdivision ** According to population subdivision b) Number of sites assigned to each stratum 1. Rural area Region Road type North Centre South and Jerusalem Total Motorways Dual-carriageway roads Other Total - rural area Urban area Town type Jewish Arab Mixed-population Total Total - all areas 70 The national seatbelt use survey is carried out in April-May (after Passover holidays), annually, since For example, the 2012 survey sample included 19,504 vehicles and drivers, 6,321 passengers on the front seats and 2,256 passengers on the rear seats; a total of 28,081 road users. The final indicators of the use of safety belts in cars in the year 2012 were as follows: - Among drivers, the level of use of safety belts was high on all types of rural roads, with a weighted value of 98%. In addition, the level of use was high in Jewish and mixed-population towns, with a weighted value of 96% in the urban area, while the level of use in the Arab towns was a bit lower - 92%. The nationwide index of the use of seat belts by drivers was 97%; 35

10 - Among passengers in the front seats, the level of use of safety belts was high on all types of rural roads, with a weighted value of 96%. In addition, the level of use of safety belts was relatively high in Jewish and mixed-population towns, with a weighted value of 93% in the urban area, while the level of use in the Arab towns was lower - 84%. The nationwide index of the use of seat belts by passengers on the front seats was 95%; - Among passengers in the rear seats, the level of use of safety belts was relatively high on all types of rural roads, with a weighted value of 77%. The level of use of safety belts was lower in the urban area, with a weighted value of 69%. The level of use in the Arab towns was very low - 42%. The nationwide index of the use of seat belts by passengers on the rear seats was 74% Use of child restraints in cars An additional SPI recommended by the SPI Manual concerned the use of child restraint systems (CRS) in cars by children below 12 years old. According to TRB-TRIS (2002), child restraint seats are 71% effective in reducing fatalities among children under the age of 5, where misuse and improper use is a critical problem both in the US and EU (Hakkert et al, 2007). Similarly to seatbelt use, the data for estimating the rate of CRS use should be collected through direct observation; however, in the case of CRS, the correct use of devices should be assessed as well (Hakkert and Gitelman, 2007). The later implies that the observational survey should be accompanied by a face-to-face interview with the car occupants, in order to get information concerning the age, height and weight of a child that should serve as a basis for judging whether the child is restrained properly. The CRS devices include front- and rear-facing child safety seats, booster seats, and seat belts, which are fitted to the age, height and weight of a child. For European countries, the rates of child use of any CRS are usually reported (e.g. Vis and Eksler, 2008), where those are produced as part of a general national survey of seatbelt use, without examination of the correctness of the CRS use. Examples of national observational surveys of CRS in cars can also be found in the US and New Zealand. In the US, the National Survey of the Use of Booster Seats (NSUBS) was carried out annually in the second half of 2000s (e.g. NHTSA, 2009). This is a probability-based nationwide child restraint survey that focuses on restraint use by children below 13. Due to the need to observe the CRS use from a close range in a slow-moving or stopped vehicle, to capture large numbers of children and to conduct interviews with the drivers, the data collection sites were selected among those with a higher probability of meeting family cars such as gas stations and parking places of recreation centers, fast-food restaurants, etc. A similar approach was adopted for setting a national observational survey of the use of CRS in cars, in Israel. The Israeli CRS survey is aimed at the examination of patterns of the CRS use among children aged 0-15, in private cars, with more focus on ages below 9. A regulation obliging the use of child safety or booster seats by children in passenger cars was introduced in Israel in 2004, where it concerns children below 8 years old. The national survey, however, relies on stricter safety rules (based on recommendations from the American Academy of Pediatrics), where the use of booster seats is recommended also for children over 8 years old, where those are shorter than 1.45 m in height. 36

11 The Israeli survey was planned at sites with a high probability to meet families with children on their way to shopping, recreational activities or long trips, in general. The observational hours were defined as throughout the whole day during school holidays (Chanuka week) and for afternoon hours on regular working days. The data are collected by trained observers who are familiar with various CRS and their correct use. At the site, the observer should approach an arriving car; document a seating position, restraint type, gender and age group of each child in the car; judge the correctness of the CRS use; ask about age, height and weight of the children in car, and conduct a short interview with an adult occupant and a child concerning the non-use of CRS (if relevant). The SPIs estimated in this survey are: the rate of proper use of the CRS (i.e. in accordance with the age, height and weight of a child), by age groups of infants (up to 1 year old), toddlers (ages 1-4), children aged 5-9, those aged and the whole group in total; the rate of non-use of the CRS, by age groups; child sitting position - the percentage of children observed in front seats, by age groups. Defining a survey size, a demand for estimation accuracy of the SPI evaluated for various age groups was considered (with 5% accuracy, at least, and 95% confidence interval) that dictated a requirement for 2,200 vehicles to be observed and a need for 63 observation sites. The survey sites were selected across all the three geographic areas of the country and in accordance with a pre-defined proportion of rural versus urban sites. In order to produce nationally representative SPIs, the raw data of child records are weighted in accordance with the distribution of child population in the country, by age groups and geographic areas considered. The national CRS use survey is conducted in December (around the Chanuka week), annually, since For example, the 2012 survey included a sample of 2,180 cars with 3,730 children aged According to the findings, among the general population of children aged 0-15, 60% were properly restrained, 33% improperly restrained and 7% not restrained at all. By age groups, properly restrained were: 53% of infants, 75% of toddlers (aged 1-4), 42% of children aged 5-9 and 64% of those aged Conversely, completely unrestrained were: 2% of infants, 3% of toddlers, 7% of ages 5-9 and 13% of ages In addition, 12% of children aged 0-15 were transported in front car seats, including 45% of infants (up to 1 year), 6% of toddlers aged 1-4, 3% of children aged 5-9 and 28% of those aged Bicycle helmet wearing The effectiveness of helmets for cyclists has been studied for decades, and they are known to reduce the risk of severe head injury by about one-third (Hakkert et al, 2007). At the same time, the legislation related to the use of safety helmets by pedal cyclists varies considerably among countries and the rate of their presence in traffic comes mostly from users awareness and country culture. An SPI concerning the daytime wearing rate of safety helmets by bicyclists was recommended by the SPI Manual, however, in the SafetyNet project, no systematic information on the usage rates was collected from the European countries. In Israel, a public discussion arose around the issue, following the introduction, in 2008, of a new regulation obliging the use of helmets by bicycle riders. In addition, 37

12 accounting for a growing use of bicycles over the last decade in the country, both for leisure and transport purposes, it was decided to set up a national survey of bicycle helmet use. Observational surveys on wearing bicycle helmets were carried out in the past in a number of countries. For example, in Finland, an annual survey of bicycle helmet use, with more than 30,000 observations, presents a part of the Traffic Behaviour Monitoring System (Luukkanen, 2003). In Sweden, a perennial monitoring takes place on the topic (Brude, 2005). In the UK, the use of bicycle helmets by riders in urban areas is followed up for about two decades, on a tri-annual basis (DfT, 2008). In addition, various regional observational surveys on bicycle helmet wearing were conducted in Canada and the US. In all the surveys, the sites and hours of observations were fitted to the target population (children, adults, riding for transport or leisure, etc.), with a wide geographic distribution of the sites; in some cases, the selection of sites was probabilistically based on population characteristics. The aim of the national survey in Israel was to estimate the level of bicycle helmet use among riders in urban areas, which use bicycles for mostly transport needs but also during leisure hours (however, excluding explicit sport or professional riders). The survey includes four types of urban sites where bicycle riders can typically be expected, such as: residential areas, city centers, entrances to bicycle parking areas (near public transportation centers, higher education institutions), and public parks/areas (which are closed for motor traffic). For each type of site, a stratified sample was built, based on the categories of town size and three geographic areas of the country and using a population size as an exposure measure. First, a town was randomly selected from a certain stratum, then, a site of the type required was found in the town chosen. The weights of the strata defined were later used for estimating national SPI values, based on the survey data. The number of sites required for the survey was defined accounting for estimation accuracy of the SPI evaluated for a stratum or type of sites (with a 5% accuracy and 95% confidence interval required). In this survey, "a site" typically presents an area, e.g. a neighborhood to be viewed, or a path - a number of streets to be passed by the observer, in pre-defined hours, aiming to collect a sample of riders observed. In total, the survey plan included 96 sites distributed throughout the country, including 36 sites in residential areas, 27 in city centers, 18 at the entrances to bicycle parking areas and 15 in public parks/areas. Concerning each bicycle rider observed, beside helmet use, the information collected includes the place of riding (e.g. roadway, sidewalk, bicycle path), riding conditions (alone, in a group, etc) and demographic characteristics of the rider (gender, age group, population group). The Israeli survey of bicycle helmet wearing is conducted in October-November, since 2009 (currently, bi-annually). For example, the 2012 survey included a sample of 6,165 cyclists, where at each type of sites a sample of 900-2,340 observations was collected. The final indicators of the use of bicycle helmets were: 16% in residential areas, 14% in city centers, 27% near bicycle parking areas, 27% in public parks/riding areas Pedestrian behavior at crosswalks The SPI Manual did not refer to pedestrian behaviour. However, in Israel, pedestrians are considered as a leading group of vulnerable road users where, over the last decade, 38

13 they typically present a third of the total road accident fatalities and about a tenth of the total injuries (Gitelman et al, 2012). In general, national surveys of pedestrian behaviour are not common in the international practice. The ETSC (2001) review stated a need for the development of SPIs for pedestrian behaviour, but did not provide examples of systematic monitoring of such. Among the European countries, the annual survey of pedestrian behaviour can be found in one country - Finland, where it is focused on pedestrian compliance with red light signals at signalized crossings in urban areas (Luukkanen, 2003). Due the magnitude of pedestrian injury in Israel, it was decided to initiate a national observational survey of pedestrian behaviour. The survey is aimed at characterization of pedestrian behaviour while crossing on an urban crosswalk. The survey's framework included three types of locations of pedestrian crosswalks: at signalized junctions, at non-signalized junctions and on street sections (non-signalized crosswalks only). For each location type, a stratified sampling of sites was applied, based on the population size and types of Israeli towns. The categories of town size can be large, medium or small, whereas the categories of town types are Jewish, mixedpopulation or Arab, in accordance with the population structure of each town. Since not all the combinations of both classifications are possible, for observations at junctions three strata were defined: small-jewish, medium-jewish and large-mixed-population towns; for midblock crosswalks - four strata, which are: small-jewish, medium-jewish, small-arab and large-mixed-population towns. Town population was considered as an indirect measure of exposure. Using the population data of Israeli towns, weighting coefficients were assigned to each stratum for each location type of the survey, which, further, were used for estimating final SPIs. The number of observations sites per stratum was defined accounting for the desired accuracy of estimates (a sampling error of 5% and a confidence level of 95%) and for the expected observation pace - average number of observations per site per hour. A twostep selection of sites was applied, where, first, a town was taken from a stratum and, second, an appropriate junction/section crosswalk was selected in the town. In addition, selecting sites, attention was given to achieving close to equal subdivision on dual- and single-carriageway roads, i.e. crosswalks with and without a refuge island between traffic directions. The final sample included 59 sites (crosswalks) distributed throughout the country, of which 19 were at signalized junctions, 19 at non-signalized junctions and 21 at street sections At each site, the observations are to continue four hours, in morning (9-13) or evening (16-20) peak hours of pedestrian activity, on weekdays only. The survey applies an external non-interventional mode of observation, where a trained observer randomly selects a pedestrian approaching a crosswalk and visually "accompanies" his/her crossing until he/she reaches the other roadside. All the pedestrian's actions are consequently recorded in accordance with a pre-defined list of pedestrian behaviours, together with basic demographic data of the pedestrian (gender, age group). Among the pedestrian behaviours examined are: non-stopping prior to crossing; crossing on red; waiting on the roadway; non-checking vehicle traffic prior to crossing; not finishing crossing during the green; crossing outside the crosswalk boundaries; pedestrian-vehicle conflicts during the crossing; using distractions (earphones, mobile phones) by pedestrians. The number of behaviours considered depends on the site's type and varies from 10 for un-divided un-signalized crosswalks to 19 for divided crossings at 39

14 signalized junctions. The SPIs estimated are the percentage of pedestrians behaving unsafely among the total number of pedestrians observed. The Israeli survey of pedestrian behaviour is conducted in November-December, annually, since For example, the 2012 survey included a sample of 5973 pedestrians. It was found that: - On crossings at signalized junctions, out of those pedestrians who approached the crossing at red, 11%-14% crossed on red and 12%-16% did not stop prior to crossing; among those pedestrians who crossed on red, 13%-22% did not check for vehicle traffic prior to crossing; 2%-19% of those who crossed on red, did so outside the crosswalk's boundaries; 5%-14% of those crossing on green, did not finish crossing during green; - On crossings at non-signalized junctions, 42%-70% of pedestrians did not stop prior to crossing. Among those who stopped, 15%-21% waited for crossing on the road and not on sidewalk; among those who did not stop, 29%-34% did not check for vehicle traffic prior to crossing and 8%-17% crossed outside the crosswalk boundaries; - At crosswalks on street sections, 41%-56% of pedestrians did not stop prior to crossing. Among those who stopped, 20%-24% waited for crossing on the roadway and not on the sidewalk; among those who did not stop, 21%-30% did not check for vehicle traffic prior to crossing and 7%-27% crossed outside the crosswalk boundaries. The scope of pedestrian distraction due to earphones was low on all types of sites, 2%-4%, where the share of using mobile phones during crossings was more tangible - 8%-17% Alcohol-impaired driving Alcohol-impaired driving is one of the recognized road safety problems throughout the world. The use of alcohol by drivers of motor vehicles increases the risk of a road accident considerably (Elvik et al, 2009; ETSC, 2010). Consequently, most countries set low legal limits for blood alcohol concentration (BAC). The SPIs for alcohol should show the state of alcohol use as a risk factor in a country at a certain time (Hakkert et al, 2007). They can be used by road safety authorities and politicians in assessing the needs for and the effects of countermeasures such as legislation, enforcement, education and publicity. According to the SPI Manual, an ideal indicator for alcohol-impaired driving would be alcohol prevalence among the general road user population, based on random breath testing. However, this SPI found to be unrealizable for European country comparisons due to judicial impediment existing in some countries and general methodological difficulties stemming from the lack of a common sampling and testing protocol, among the countries. Nevertheless, random breath testing surveys for monitoring the level of alcohol-impaired driving are conducted in some countries, e.g. the Netherlands and Finland, where a time series of such SPI covers more than two decades. Usually, a random breath testing survey is conducted at high-risk times (e.g. weekend nights) but at regular travel sites, where a substantial amount of drivers (tens of thousands) are stopped and checked. In Israel, the maximum permitted BAC is 0.5 g/l. The extent of drink-driving in the country was underestimated in the past. Today, conservative estimates indicate that alcohol is a contributing factor in 7-15% of fatal crashes in Israel (OECD/ITF, 2013). Since the mid 2000s, enforcement and public information concerning drink-driving have 40

15 increased, where those are focused mostly on high-risk times (nights, weekends, holidays), in high-risk places (in the vicinity of pubs) and on high-risk populations (young drivers). In line with the increasing attention to drinking and driving, it was decided to carry out a national survey, to examine the level of alcohol-impaired driving in the country. However, as random breath testing in Israel was at its initial stage, where the police checks take place mostly at high-risk places (near pub areas), the survey sites were selected not on the general road network but on traffic arterials leading to and from the "hazardous spots" - pubs and night activities' areas. Practically, the measuring sites were selected on main urban/suburban roads, at a distance of about 1 km from the "hazardous spots", based on a full list of 15 such spots distributed throughout the country that was received from the Traffic Police. For each spot, three survey sites were sought for, on the adjacent roads. In line with similar surveys abroad, the sobriety checks were planned on weekend nights. A breath testing survey is heavily dependant on cooperation with the Traffic Police and, thus, is restricted by the police forces dedicated to the survey's performance. The survey was planned at 43 measuring sites (around 15 spots as mentioned above), where at each site a strengthened police team was planned to be situated, enabling to carry out the checks of every or randomly selected vehicles in the survey hours, without manpower limitations related to the need of treating drivers caught under the influence of alcohol during the survey. Accounting for other needs of the police, the survey time was limited to two hours at each site, yet the "time windows" were equally distributed between 1 and 5 a.m. As a sufficient amount of sites was planned for each geographic area (13-15 sites), a stratified sample was designed, where the weights of the strata were assigned in accordance with the population size and further applied for estimating final values of SPI. To estimate the level of alcohol-impaired driving, two SPIs were defined: (1) the share of "drunk" drivers according to the law, following evidential breath testing, and (2) the share of drivers suspected of drink-driving, following screening breath testing. The SPI values were planned to be estimated as national (weighted) figures and per stratum (geographic areas). The number of observations required was defined as a minimum value based on the desired accuracy of final estimates (a sampling error of 2% and a confidence level of 95%) and assuming the observation pace - the number of drivers checked in two hours of survey. A sample of 3,000 drivers checked was planned for the survey. During the survey, the police teams were accompanied by observers who should collect the data on every driver checked, including gender, age, vehicle type, the number of car occupants. The first national survey of alcohol-impaired driving in Israel was carried out in November 2011 and included 1703 drivers checked. The survey performance was not uniform across all the sites. The survey was performed properly, i.e. in accordance with the framework designed, at 22 sites. Based on the data of sites with proper survey performance, the national estimates of the share of "drunk" drivers (over the legal BAC level) was 2.9% and of those suspected of drink-driving - 6.7%. 41

16 2.7. Statistical methods for estimating national SPIs Examples of techniques for estimating SPI values and their confidence intervals can be found in the SPI Manual (Hakkert and Gitelman, 2007). A similar approach for estimating final SPIs was adopted for processing national observational surveys in Israel. A typical method for estimating final SPI using stratified sample data is described below. Let us consider an observational sample composed of three strata: A, B, C (for example, various road categories), where each stratum includes a number of sites; for example, stratum A includes H sites. The SPI is defined as the proportion of units having a certain feature (e.g. drivers using seatbelts) out of the total units observed. The estimation of a final (national) SPI includes two steps. First, an SPI value per stratum (e.g. stratum A) is estimated as p h H h 1 w h p h where: p h - the proportion of units having a certain feature at site h; w h - the weight of site h; H - the total number of sites for this stratum. Usually, the site weights are assigned according to the number of units (vehicles or road users) observed at the site, where: H w h h 1 1. The 95%-confidence interval of the above estimate will be: [ p 1.96 Var ( p); p 1.96 Var ( p)] where: H 2 ph (1 ph ) Var ( p) wh h 1 nh (2) n h - the number of units observed during the survey at site h; p h, w h, H as described above. Then, a final SPI, for the whole population, is estimated as SPI C i A λ i SPI_i where: SPI_i are separate SPIs, for each stratum; i designates the stratum weight, where A + B + C =1. The 95%-confidence interval of the above estimate will be: [SPI Var(SPI);SPI Var(SPI)] (4) where: C Var(SPI) λ 2 Var(SPI_i). i i A (1) (3) 42

17 The over-time changes of national SPIs in Israel are monitored by means of a visual presentation of their values on a time-line. To examine a significance of changes, the values of two consequent years are compared using a method developed by the Technion Statistical Laboratory (Doveh, Cohen, 2010). 3. EXAMPLE: NATIONAL SPEED SPIS IN 2012 The framework of the national speed survey in Israel was described in Sec.2.1. As an example, this section illustrates the results of a national speed survey which was carried out on the Israeli road network in June Table 3 shows final speed SPIs estimated for various rural road categories, in daytime hours. For each lane on each road type, the values and confidence intervals are given for the mean speed, the 85th percentile of speed, the percentage of vehicles over the speed limit and the percentage of vehicles travelling at high speeds. The numbers of vehicles observed in the survey (in free-flow conditions) are also indicated. Figure 3 provides a visual presentation of the mean speed SPIs and their confidence intervals, for rural roads. According to the 2012 survey's findings (in day and night hours), on rural roads, the 85th percentiles of speeds were higher than the speed limits on all road types, as follows: by kph on motorways, by kph on dual-carriageway roads without at-grade junctions, by kph on other dual-carriageway roads (with at-grade junctions), by kph on single-carriageway roads, by kph on local roads. The share of vehicles travelling at speeds over the speed limits, in free-flow hours, was: 40%-50% on motorways, 50%-60% on dual-carriageway roads without at-grade junctions, about 60% on other dual-carriageway roads, about 70% on single-carriageway roads, about 40% on local roads. Thus, all rural road types are associated with a significant share of noncompliance with speed limits, where the highest level of non-compliance was observed on dual-carriageway roads with at-grade junctions and on single-carriageway roads. In urban areas, the 85th percentile of speeds was higher than the speed limits: by 4 kph in the right lanes (in night hours only) and by 7-9 kph in the left lanes of arterial roads, by kph on central collector streets (dual-carriageway) and by 4-10 kph on residential collector streets (single-carriageway). The share of vehicles travelling over the speed limits, in free-flow hours, was: 20%-40% on arterial roads, about 60% during day hours and 70% during night hours on central collector streets, 25%-40% on residential collector streets. Thus, among the urban road types, the highest speeds were observed in the left lanes of arterial roads, where the major speeding problem is associated with dual-carriageway collector streets situated in city centers (with 50 kph speed limits). Figure 4 provides a comparison of mean speeds and the percentage of vehicles over the speed limit, by road type, in 2012 versus 2011 (in daytime hours). Both visual and statistical examinations of changes in speed SPIs demonstrated no essential changes in travelling speeds on the Israeli road network in the year 2012 versus

18 Road type Table 3. Survey 2012: Speed SPIs estimated for rural road types, in daytime hours No of vehicles measured Mean speed, kph 95% confidence SPI interval 85th percentile of speed, kph 95% confidence SPI interval Percentage of vehicles over the speed limit 95% confidence SPI interval Percentage of vehicles travelling at high speeds 95% confidence SPI interval Motorways - right lane 16, % 32.4% 33.8% 5.6% 5.3% 6.0% Motorways - left lane 14, % 72.5% 73.9% 12.9% 12.4% 13.5% Motorways - both lanes 30, % 51.2% 52.2% 9.0% 8.7% 9.3% DCR without at-grade junctions - right lane 11, % 27.9% 29.5% 0.3% 0.2% 0.5% DCR without at-grade junctions - left lane 13, % 72.3% 73.7% 4.3% 4.0% 4.7% DCR without at-grade junctions - both lanes 24, % 52.8% 53.8% 2.6% 2.4% 2.7% Other DCR - right lane 70, % 41.3% 42.0% 4.5% 4.3% 4.6% Other DCR - left lane 83, % 68.1% 68.6% 16.2% 16.0% 16.4% Other DCR - both lanes 153, % 55.9% 56.3% 10.8% 10.7% 11.0% Single-carriageway roads 84, % 69.3% 69.9% 3.7% 3.5% 3.8% Local roads 33, % 39.1% 39.9% 2.8% 2.6% 2.9% DCR dual-carriageway roads 44

19 Note: DCR dual-carriageway roads Figure 3. Survey 2012: mean speed SPIs and their confidence intervals (CI), for rural roads (daytime hours) In 2012, the automatic speed enforcement program was launched on the interurban road network in Israel, with tens of speed cameras installed on selected rural road sections. It appears that at the time of the current speed survey (June 2012), the program did not grow up to the scope that would impact the level of travel speeds on the road network. 4. DISCUSSION Safety performance indicators are defined as measures reflecting the operational conditions of the road traffic system which influence the system s safety performance. They belong to intermediate outcomes of the road safety pyramid and are called to characterize the current state of the system, as to the factors that lead to accidents/injury, but in addition to accident or injury numbers (Hakkert et al, 2007). The importance of an SPI representing a certain factor is assessed in terms of the strength of its relationship with accident or injury occurrence, the scope of the factor's contribution to accidents/injury and whether it can be influenced by road safety measures. Besides, SPIs should be measurable and more general than outputs of particular interventions. In the international practice, the frequently used SPIs are those reflecting the areas of road user behaviours and, particularly, speeds, alcohol-impaired driving and the use of restraint systems in cars, due to an evident relationship between those behaviours and accident/injury occurrences. 45

20 a mean speed SPIs b percentage of vehicles over the speed limit SPIs 2 Figure 4. Comparison of mean speeds and the percentage of vehicles over the speed limit, by road type, in 2012 versus 2011 (daytime hours) Over the last decade, a growing interest of international bodies is observed in the use of SPIs for country comparisons (e.g. ETSC, 2010; OECD/ITF, 2013), where countries are encouraged to establish national systems for monitoring road user behaviours. SPIs are considered as useful tools for supporting road safety management, as they may assist in assessing the current state of the road traffic system, monitoring road safety progress, 2 Note: DCR dual-carriageway roads 46