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SWOV research for ERSF: Road safety measures for interurban roads

 

The European Commission decided to set up a Working Party 'Infrastructure', to recommend a limited number of road safety measures suitable for application in the short term. The activities should focus on interurban roads because these roads are relatively dangerous. According to the country, between 50 and 70% of all road fatalities occur on them. A report on this matter was compiled by SWOV on behalf of the European Road Safety Federation (ERSF) (R-95-18).

About 90% of all casualties on non-motorway roads outside built-up areas can be connected with just four kinds of manoeuvre:

Part of driving task

Nature of most accidents

Approx.%

A Keeping course

Going off the road

35

B Intersecting

Collisions with intersecting vehicles

20

C Following

Rear-end collisions

15

D Overtaking

Head-on collisions

20

All percentages mentioned are slightly lower on roads passing through villages because, there, a fifth type of accident (E), i.e. collisions with vulnerable road users such as pedestrians or cyclists, occur more often (around 15%). The average consequence of this type of accident is usually more serious. Measures to combat road hazard, mostly called 'countermeasures', should focus on the prevention of these five kinds of accidents.

 

Questionnaire

A questionnaire was sent out to the Member States asking for relevant information on the subject. It was the intention to base the subsequent selection of the measures mainly on the answers to this questionnaire. The measures (in the broad sense of the word) to be selected must be those most likely to lead to a decrease in the number of road victims in the short term. An indication of the effect of each measure on road safety should possibly be given, together with the preferred order of priority among the measures. An international review of the road safety situation must be added, to show the scope and the nature of the problem.

 

Ten countermeasures

The study has resulted in the selection of ten countermeasures. A distinction is made between countermeasures on three levels: analyses, traffic engineering and traffic operation. A separate column in the table indicates which of the five manoeuvre categories mentioned might be addressed by each countermeasure.

No

Countermeasure

Manoeuvre

Analyses

1

Road, traffic and accident data collection

all

2

Road safety inspection

all

3

Black spot analysis and treatment

all

4

Road safety impact assessment (RIA)

all

Traffic Engineering

5

Traffic calming on thoroughfares through small towns and villages

B E

6

Building roundabouts instead of intersections

B

7

Safety barriers at hazardous locations

A

8

Restricting the possibility of overtaking

D

Traffic operation

9

Consistency in the signing and marking of (sharp) bends

A

10

Alternative routing of slow traffic

E

 

 

Attractiveness of the countermeasures

One of the factors -though definitely not the only one - determining the attractiveness of a countermeasure to be taken is its cost-effectiveness. Three groups of countermeasures can be formed, with different degrees of cost-effectiveness. (A high cost-effectiveness means that the money is well spent). There is also a group for which no cost-effectiveness could be established.

 

No cost-effectiveness to be established

1 Road, traffic and accident data collection

2 Road safety inspection

3a Black spot analysis

4 Road safety impact assessment (RIA)

 

Relatively high cost-effectiveness

3b Black spot treatment

6a Building small roundabouts instead of intersections

9 Consistency in the signing and marking of (sharp) bends

10a Alternative routing of slow traffic without building parallel link

 

Medium cost-effectiveness

5 Traffic calming on thoroughfares through small towns and villages

7 Safety barriers at hazardous locations

 

Relatively low cost-effectiveness

6b Building large roundabouts instead of intersections

8 Restricting the possibilities of overtaking

10b Alternative routing of slow traffic with the building of parallel links

 

In the mean time SWOV has been asked by the ERSF to conduct another study on this subject. The project is called Intersafe and the goal is to prepare a Technical Guide, describing the current practice on certain values which influence road safety most. The study provides the latest information in order to clear up confusion and to harmonise opinions. It gives the optimal values together with the reasoning behind their selection. The results, as a compilation of ready for use knowledge, will be suitable for designing and operating road with special regard to road safety.

SWOV Research Activities 5 - March 1996

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