Press release

Motorists need to be informed about the safe use of Advanced Cruise Control (ACC). Research of the Institute for Road Safety Research SWOV has shown this is necessary. If used incorrectly ACC can result in more crashes, even though it increases driving comfort ánd can contribute to safety.

Advanced Cruise Control is a type of cruise control which not only limits the driving speed to the speed set by the driver (as is the case in a conventional cruise control), but which also keeps an eye on vehicles ahead. As soon as the ACC system detects a vehicle in front, it calculates the distance and speed difference, and then adapts its own speed in order to maintain sufficient distance.

A SWOV literature study of various Netherlands and foreign research results showed that ACC on a motorway with relatively little traffic and a good view can contribute to a safer journey. ACC users appear to drive in those situations with a slower average speed and with less speed fluctuations. There is also less tailgating, and drivers get tired less quickly because of the greater driving comfort. However, ACC has a negative road safety effect in busy traffic circumstances. Then, drivers have a faster average speed and tailgate more. Another worry is that, when using ACC, the driver's alertness decreases. This leads to a slower reaction to vehicles ahead and to those from the right (braking suddenly and with full force) in critical situations.

SWOV recommends informing drivers about the circumstances, during which ACC can be used safely. These circumstances are: during motorway journeys if there is not much traffic and the view and weather are good.

ACC use should be discouraged in busy traffic on motorways, on secondary roads where overtaking is allowed, and where there are many intersections. The report shows that on bending, secondary roads and on urban roads, ACC use is ill advised. The reason for this is that vehicles ahead, when going round a bend, can be out of sight of the sensors, whereby the system no longer functions properly. Furthermore, if an oncoming vehicle during a bend comes into view of the sensors, the system can suddenly brake one's own vehicle.

Motorists that have to be informed about the safe use of ACC must be advised to control the system regularly. SWOV regards the driving course as one of the possibilities for providing such information.

The full report Advanced Cruise Control and Road Safety (R-2003-24) which is in Dutch but has an English summary, can be consulted online.