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Intelligent roads

Tests on a simulator (with the vehicle approaching a dangerous bend) found that an automatic speed limiter system slowing down the vehicle without any intervention by the driver was particularly unpopular with motorists.

Over 42 000 people died on Europe's roads in 1998. Speed is not the only cause of these tragedies, but it is a decisive factor. What role does speed play, depending on the roads and conditions? What can be done to gain acceptance for speed limits? Is it a matter of persuasion or compulsion? How could technology help to solve this problem? What makes a road safe? These are just some of the questions analysed by the research teams working on the Master (Managing Speeds of Traffic on European Roads) project. They are convinced that speed equals danger.


According to some estimates, slowing traffic down by an average of just 1 km/h would reduce the number of road accidents by 2-3%. The next question is how to raise the awareness of motorists steeped in a culture where speed has a more positive image. For two years researchers from eight European countries studied the many different ways currently used (or under development) in the European Union to ease the driver's foot off the accelerator pedal. The principal objective was to compile an inventory of duly analysed best practice for the public authorities. One central message pervades the final report on the study: there is no panacea. Instead, the researchers advocate a mix of solutions, depending on the type of environment (motorways, country roads, urban roads, etc.) and drawing on the latest developments in information and communications technology, though not systematically.

GPS to slow down cars

Some drivers are already familiar with certain advanced transport telematics (ATT) systems, such as variable message signs displaying recommended or mandatory speed limits, depending on traffic density or weather conditions. Other tools are being developed to equip vehicles to receive information from the outside world and suggest a response to the driver (via screens in the car, for example) or even, in certain critical situations, act in place of the driver. The most innovative instrument of this type, currently being studied by several carmakers, is the variable speed limiter.

'The system automatically adapts the speed of the vehicle to the situation,' explains Veli-Pekka Kallberg, the coordinator of the Master project. 'It can be activated on passing a speed limit sign or when there is fog, poor visibility or other potentially dangerous conditions. It takes the form of an active accelerator pedal which, in fact, exerts a counter-force whenever the driver attempts to exceed the authorised speed. The signal activating the limiter can be sent by a roadside transmitter or even via a GPS-type system, which tracks the car's position in traffic at all times.'

Tests designed to gauge the efficiency of the system as a vehicle approaches a dangerous bend were conducted on a driving simulator during the Master project. They showed that the speed limiter works better than leaving the driver - who is fully informed of the vehicle's speed via a roadside or in-vehicle screen - to decide. Other tests, this time on the road, reached less black-and-white conclusions. They were able to demonstrate the limiter's effectiveness, but only in certain conditions, in this case on urban roads. 'In terms of driver acceptance, the speed limiter is the least popular system,' adds the project coordinator.

Self-explaining roads

Other road management methods - less high tech than ATT, but not to be neglected - were also explored, in particular, the self-explaining road concept. 'The best example is motorways,' continues Mr Kallberg. 'Their appearance leaves no doubt about what sort of road they are: several wide lanes, one-way traffic, no bicycles, no crossroads - it's quite clear. Unfortunately, this is not the case on many other types of road, particularly in urban areas. We need a system consisting of a limited number of types of road, each with clearly differentiated identities.'

This self-explaining roads concept means choosing distinctive features, such as surfacing, lane width, presence or lack of cycle paths, width of pavements, etc. On a driving simulator, researchers working on the Master project singled out two aspects to which drivers seem particularly receptive: cycle paths and road width.

Along the same lines, the report stresses the need to adapt roads to their environment, particularly when they pass through residential areas. They could include chicanes, noisy markings, narrowing of the road, traffic islands, mini-roundabouts, noisy or coloured surfaces, gateways at the entrances of villages, etc. Several studies have concluded that layouts like this could cut the number of serious accidents by 30% to 50%.

The partners working on Master also feel that road safety in Europe would improve substantially if speed limits were generally tighter. For example, they recommend lowering the limit to 30 km/h in purely residential urban streets (instead of the 50 km/h or 60 km/h currently allowed in many countries).

One final point: the big differences in legislation from one country to another are an added danger. On motorways, for example, the speed limits range from 90 km/h in Norway to 130 km/h in Italy, France and the United Kingdom. And there is no speed limit at all on most motorways in Germany.

Managing Speeds of Traffic on European Roads (MASTER)



Veli-Pekka Kallberg
Technical Research Centre of Finland (VTT)
Fax : +358-9-464850
E-mail :

René Bastiaans
European Commission, Directorate-General for Energy and Transport (DG TREN)
Fax : +32 2 29 68350
E-mail :

- Technical Research Centre of Finland (VTT), Espoo, Finland (coordinator)
-Transport Research Laboratory (TRL), Crowthorne, United Kingdom
-Lund University - Department of Traffic Planning and Engineering, Lund, Sweden
-Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden
-Netherlands Organisation for Applied Scientific Research (TNO), Delft, Netherlands
-University of Leeds - Institute for Transport Studies (ITS), Leeds, United Kingdom
-Ingeniera de Trafico (INTRA S.L.), Barcelona, Spain
-Institute for Road Safety Research (SWOV), Leidschendam, Netherlands
-University College London - Institute for Transport Studies (ITS), London, United Kingdom
-FACTUM Chaloupka, Praschl, Risser OHG, Vienna, Austria
-Institute for Transport Sciences Ltd (KTI), Budapest, Hungary
-Instituto Superior Técnico (TRANS-POR), Lisbon, Portugal

Adapting driving restrictions to the environment, particularly in residential areas, could cut the number of serious accidents by 30% to 50%.