In the report of late 2001 Safe, What is Safe?, SWOV indicated how the annual number of traffic casualties could be reduced considerably. These proposals were to be regarded as an addition to the proposals as were developed in the then National Traffic and Transport Plan of the Ministry of Transport (NVVP). In Safe, What is Safe? it was, among other things, suggested to do more about speed control. The Ministry of Transport asked SWOV to investigate the possibilities for this to be used the coming years. An interesting possibility of regulating the vehicle speed on the road are the systems for intelligent speed adaptation (ISA systems). These systems can support the driver at different levels. They can only inform, but also warn and possibly advise. There are also ISA systems that intervene: the driving task is supported actively or even partly taken over. This study provides an overview of various systems of intelligent speed adaptation and possible future developments. There are indications that ISA reduces and homogenizes speeds. Positive road safety effects may be expected. However, compensation behaviour is also reported: on road stretches were there is no ISA, drivers are inclined to drive faster. The support among drivers is the greatest for a warning ISA version and for use in urban areas. An implementation process is recommended, in which ISA has an ever greater functionality and is integrated with other systems. Safe speeds and dynamic traffic information should also be supported. Apart from this, it is recommended that ISA systems should be voluntary and easy to overrule. The general conclusion can be that ISA systems are promising and that there is every reason to work on further developments. However, it may not be expected that the introduction of ISA will be widespread during the coming 10-15 years. This is why it is not recommended to wait for the introduction of ISA before having a speed control policy for the coming 10-15 years. Speed control still relies on the traditional instruments, such as road design, police surveillance, and campaigns.
Abstract