Unsafe & safe road way design for urban roads

Size: px

Start display at page:

Download "Unsafe & safe road way design for urban roads"

Brenda Ross
5 years ago
Views:

1 PIARC International Road Safety Seminar Beijing October 2005 Unsafe & safe road way design for urban roads Hans-Joachim Vollpracht Piarc TC 3.1 Chairman

2 Main objective of urban planning & development The reduction of the motorized traffic as far as possible e.g. by: - separating the through traffic from local traffic, - a good offer of public transport, - parking restrictions, - pedestrian zones and - a network of biking routes. But urban road design remains a challenge for urban developers and road engineers to create safe solutions in situations which are characterized by:

3 General chalange of urban road design Mixed composition of traffic with vehicles, trucks, busses, motorcycles and most vulnerable users like pedestrians and bicyclists A variety of different functions like connection, distribution, access and stopover Different activities on the roads like public and private transport of goods and people, shopping, road business, parking and loading, children s s playground etc

Connection Urban main road With mixed traffic And mixed

4 Differences to interurban roads Three lane-interurban express Road With separation of traffic And only one function: Connection Urban main road With mixed traffic And mixed functions, Connection, Distribution and Access how to improve?

5 Principles for Urban Road Design Different use and functions within the urban road network need different and unmistakeable design and measures for road safety Different compositions of traffic (e.g. High traffic volume of goods or public transport) need different solutions No dynamic design for urban roads! Through roads and urban roads must only fulfil the geometrical needs of vehicles, cyclists and pedestrians (Geometric Design)

6 1 Design different roads for different types and functions Four types of urban roads

7 Design and speed: Speed is the main problem for vulnerable road users: pedestrians and cyclists In the case of a collisions with cars they survive up to 30 km/h! Stopping sight distance has to be short in residential areas

8 The faster we drive the farer we focus ahead Reverse conclusion. 600m 500m 400m 300m 200m 100m 300m 300m 0m Speed-related focus (point of fixation): 100km/h = 600m 65km/h = 350m 100 km/h 80 km/h 65 km/h The farer we look ahead the faster we drive and the smaller is our angle of view Roth 1973 in: Cohen 1984

9 The farer the focus, the faster the speed! Rural road: small field of view. Drivers can t see the intersection. Urban road: far point of fixation. Drivers increase speed.! B 109/140 Groß-Schönebeck-Gollin / Mühlenstraße Berlin

10 Design roads as an arrangement of urban rooms (spatial sectors, places etc!) Arrangement of spatial sectors...to keep speed down OD-Guideline for urban roads / Germany

11 Unsafe Cross sections for urban situatations (dynamic design) Lane width is 3.50m, focus is far away, speed about 80 km/h and Crossing bridges for pedestrians are not accepted

12 Width of carriageways and lanes (geometric design) for a speed of 50 km/h

13 Geometric Design of the cross sections And Vehicle Capacity The vehicle capacity depends primarily on the design of the junctions and secondly on the number of lanes of the carriageway but not on their width! The capacity can be: 2-lane carriageway veh/h Standard with of carriageway = 6,50 m Low volume of bus and goods traffic = 6,00 m Extreme high volume of Busses and trucks = 7,00 m 4-lane carriageway veh/h Standards lane width is 3,00 3,25 m

14 4-lane carriage way 4-lane carriageway with median stripe: - Safe solution for crossing 6,50 m 2 m 6,50 m 15,00 m pedestrians 4-lane carriageway (without median stripe) 5,50 m 5,50 m m

15 Example from Berlin Measures for safe pedestrian crossing 4-lane carriage way with median stripe Pedestrian traffic signal Barrier for pedestrian crossing in junction area

16 Urban Intersections have to be......visible, clear, recogniseable & walk able)

17 Roundabouts are the safest urban intersections on one level outboard-ring (B) : inboard-ring (paving) -Pedestrian way -Cariage way -Plaster ring -Pedestrian crossing 2,5 : 1 Example: B=6,5m inboard-ring 2,00m

18 The entrance into round abouts is......radial to the centre with low speed Not tangential with high speed into the circling traffic!

19 Width of pedestrian facilities

20 Separation of transport modes Width of cyclist facilities

21 2-lane carriage way Variation: 2-lane with cyclist facility Recommended by GDV (research institute of the German assurance federation) Quelle GDV

22 2-lane carriage way Variation: 2-lane with cyclist facility Safe solution for pedestrian and cyclists Recommended by GDV (research institute of the German assurance federation) Quelle GDV

23 Excelent Chinese solutions

24 Separation of transport modes Width of public transport stop facilities

25 Width of public transport stop facilities Crossing aid

26 Lanes for Buses and delivery Parking in an extra wide median stripe and bus-lane Example from Berlin source: Straßen und Plätze neu gestalten Kirschbaum Verlag

27 Separation of public transport Median stripe for tram-line tram mixed use of the right lane, Bus lane in rush hour, other time parking

28 Traffic calming measures to support speed limits and to ease the crossing of pedestrians Traffic island in section with high frequency of crossing pedestrians -No median strip in section with parking, good sight with cyclist lane - Calmed speed level (Source: German insurances)

29 Variation: 2-lane with median strip - much safer solution for pedestrians, in areas with high volume of crossing pedestrians 2-lane carriage way Recommended by GDV (research institute of the German assurance federation) Example with and without cyclist facility Quelle GDV

30 2-lane carriageway Variation: 2-lane with median strip Left: before - accidents in 2 years without median strip Right: after - accidents with median strip or traffic island Pedestrian Quelle GDV 30

31 sustainable enforcement by road design) Use transition measures to support speed limits when entering build up areas

32 Measures to support speed limits Traffic islands

33 Measures to support speed limits: Traffic calming with... humps and bumps

34 Conclusions > Reduce individuel motorized traffic as far as possible. > Design a hierarchy of four to fife road categories for different functions and speed limits. > Avoid long straight roads and design sequences of short urban rooms or places. > Avoid dynamic design and fulfil the geometric needs of transport modes only. >Separate the most vulnarable users from motorized traffic. > Use traffic calming design to support speed limits and to improve safety of pedestrians and bicyclists

Why do we need checklists?

Why do we need checklists? Support for Implementing Measures for the South East Core Regional Transport Network Multi Annual Plan (EuropeAid/125783/C/SER/MULTI) The RSA Checklists core part of the Manual (RSA part 2) by L. Pfeiffer