Unsafe & safe road way design Unsafe & safe road way - - PowerPoint PPT Presentation

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PIARC International Road PIARC International Road Safety Safety Seminar Seminar Beijing 18 Beijing 18 – – 20 20 October October 2005 2005

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

Hans-Joachim Vollpracht Piarc TC 3.1 Chairman

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Main Main objective

• bjective of urban
• f urban

planning planning & & development development

• The reduction of the motorized traffic as far as

The reduction of the motorized traffic as far as possible e.g. by: possible e.g. by:

• separating the through traffic from local traffic,

separating the through traffic from local traffic,

• a good offer of public transport,

a good offer of public transport,

• parking restrictions,

parking restrictions,

• pedestrian zones and

pedestrian zones and

• a network of biking routes.

a network of biking routes.

• But urban road design remains a challenge for

But urban road design remains a challenge for urban developers and road engineers to create safe urban developers and road engineers to create safe solutions in situations which are characterized by: solutions in situations which are characterized by:

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General General chalange chalange of

• f

urban urban road road design design

• Mixed composition of traffic with vehicles,

Mixed composition of traffic with vehicles, trucks, busses, motorcycles and most trucks, busses, motorcycles and most vulnerable users like pedestrians and vulnerable users like pedestrians and bicyclists bicyclists

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variety

• f

different functions like A variety

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different functions like connection, distribution, access and connection, distribution, access and stopover stopover

• Different

Different activities on the roads like public activities on the roads like public and private transport of goods and people, and private transport of goods and people, shopping, road business, parking and shopping, road business, parking and loading, children loading, children’ ’s playground etc s playground etc

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Differences to interurban roads 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?

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Principles for Urban Road Design 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).

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Design different roads for different types and functions.

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Four types of urban roads 50 10

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Design and speed: Design and speed:

Speed is the m ain problem for Speed is the m ain problem for vulnerable road vulnerable road users: pedestrians and cyclists users: pedestrians and cyclists

In the case of a collisions with cars they survive up to 30 km/h In the case of a collisions with cars they survive up to 30 km/h ! !

Stopping sight distance Stopping sight distance has to be short in has to be short in residential areas residential areas

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The faster we drive the farer we focus ahead Reverse conclusion…. The farer we look ahead the faster we drive and the smaller is our angle of view

Roth 1973 in: Cohen 1984

600m 500m 400m 300m 200m

300m 300m

100m

300m

0m

100 km/h 80 km/h 65 km/h

Speed-related focus (point of fixation): 100km/h = 600m 65km/h = 350m

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The farer the focus, the faster the speed! The farer the focus, the faster the speed!

B 109/140 Groß-Schönebeck-Gollin / Mühlenstraße Berlin

!

Rural road: small field of

• view. Drivers can’t see the

intersection. Urban road: far point of

• fixation. Drivers increase

speed.

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OD-Guideline for urban roads / Germany 2002

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Arrange- ment of spatial sectors

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Design roads as an arrangement of urban rooms (spatial sectors, places etc!) ....tokeep speed down

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Unsafe Cross Unsafe Cross sections sections for for urban urban situatations situatations ( (dynamic dynamic design design) )

Lane width is 3.50m, focus is far away, speed about 80 km/h and Crossing bridges for pedestrians are not accepted

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W idth of carriagew ays and lanes ( geom etric design) for a speed of 50 km/h

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Geom etric Design of the cross sections And Vehicle Capacity

The vehicle capacity depends primarily on the design

• f the junctions and secondly on the number of lanes
• f the carriageway but not on their width!

The capacity can be:

2-lane carriageway 1400 -2200 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 1800 - 2600 veh/h

Standards lane width is 3,00 – 3,25 m

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4 -lane carriage w ay

4-lane carriageway with median stripe:

• Safe solution for

crossing pedestrians

4-lane carriageway (without median stripe)

6,50 m

2 m 6,50 m 15,00 m 5,50 m 5,50 m 11.00 m

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4 -lane carriage w ay with median stripe

Example from Berlin Measures for safe pedestrian crossing Barrier for pedestrian crossing in junction area Pedestrian traffic signal

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Urban Urban I ntersections I ntersections have have to to be be .... ....

......visible, clear, recogniseable & walk able)

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• utboard-ring (B) :

inboard-ring (paving) 2,5 : 1 Example: B= 6,5m in- board-ring 2,00m

• Pedestrian way
• Cariage way
• Plaster ring
• Pedestrian

crossing

Roundabouts are the safest urban Roundabouts are the safest urban intersections on one level intersections on one level

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The The entrance entrance into into round round abouts abouts is.... is....

Not tangential with high speed into the circling traffic! ...radial to the centre with low speed

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W idth of pedestrian facilities

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Width of cyclist facilities

Separation of transport modes

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2 -lane carriage w ay

Variation: 2-lane with cyclist facility

Recommended by GDV (research institute of the German assurance federation) Quelle GDV

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2 -lane carriage w ay

Variation: 2-lane with cyclist facility

Safe solution for pedestrian and cyclists

Recommended by GDV (research institute of the German assurance federation) Quelle GDV

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Excelent Excelent Chinese solutions Chinese solutions

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Width of public transport stop facilities

Separation of transport modes

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W idth of public transport stop facilities

Crossing aid

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Lanes for Buses and delivery Lanes for Buses and delivery

Parking in an extra w ide m edian stripe and “bus-lane”

Example from Berlin

source: “Straßen und Plätze neu gestalten” Kirschbaum Verlag

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Separation of public transport

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

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Traffic calming measures to support speed limits and to ease the crossing

• f pedestrians

Traffic island in section w ith high frequency of crossing pedestrians

• No m edian strip in section w ith parking, good sight w ith cyclist

lane

• Calm ed speed level

(Source: German insurances)

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2 -lane carriage w ay

Variation: 2-lane with median strip

• much safer solution

for pedestrians, in areas with high volume

• f crossing pedestrians

Recommended by GDV (research institute of the German assurance federation)

Example with and without cyclist facility

Quelle GDV

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2 -lane carriagew ay Variation: 2-lane with median strip

Quelle GDV

Left: before - accidents in 2 years

without median strip

Right: after - accidents with median

strip or traffic island

Pedestrian

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„sustainable enforcement „ by road design)

50 50 50 Use transition measures to support speed limits when entering build up areas

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Measures to support speed limits

Traffic islands

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Measures to support speed limits: Traffic calming with…

..... humps and bumps

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Conclusions Conclusions

> > Use

Use traffic traffic calming calming design design to to support support speed speed limits limits and to and to improve improve safety safety of

• f pedestrians

pedestrians and and bicyclists. bicyclists.

> > Reduce individuel motorized traffic as far as possible Reduce individuel motorized traffic as far as possible.

.

> > Design a hierarchy of four to fife road categories for Design a hierarchy of four to fife road categories for different functions and speed limits. different functions and speed limits. > > Avoid long straight roads and design sequences Avoid long straight roads and design sequences

• f short urban rooms or places.
• f short urban rooms or places.

> > Avoid dynamic design and fulfil the geometric needs Avoid dynamic design and fulfil the geometric needs

• f transport modes only.
• f transport modes only.

> >Separate the most vulnarable users from motorized traffic. Separate the most vulnarable users from motorized traffic.