High speed has an adverse effect on road safety. Various attempts have been made to reduce traffic speed. Intelligent speed adaptation (ISA) is an ‘in car’ alternative to ‘traditional’ speed reduction measures such as police speed checks and speed ramps. ISA systems work by actively or passively warning the driver or limiting the vehicle when the prescribed speed limit is exceeded, depending on where the vehicle is at that moment. Promising pilots have been conducted in the Netherlands and Sweden, which suggest that ISA could be a useful concept for the future. The current trend in the motor industry is to develop more incar systems to support the driver which can intervene and/or advise on driving speed. There are three systems. The first is the standard Cruise Control (CC) which maintains a set cruising speed. The Intelligent Cruise Control (ICC) is a CC which also regulates the distance from vehicles in front. Finally, there are speed limiters which help the driver to not exceed a certain self-selected driving speed. This may be through giving a warning signal or through the active intervention of a speed limiter which prevents the car from exceeding the set speed even if the accelerator is further depressed (hereafter referred to in this report as the hard limiter). To be able to judge whether such systems have a positive effect on achieving the policy goals of improved road safety, traffic circulation and environment, the Ministry of Transport, Public Works and Water Management (Ministerie van Verkeer en Waterstaat) decided to have a user study carried out. This user study addressed three related research questions with supporting studies. 1. Interviews with drivers of cars fitted with different in-car speed controlling systems. What is important to drivers? (qualitative: why). Thirty car drivers were interviewed in total, which included: • 13 about the ICC; • 11 about a speed limiter: (6 with warning signal, 4 with hard limiters and 1 with both). • 12 about the CC (of which 6 car drivers were also asked about the speed limiter). 2. A survey among drivers of Nissan Primera cars fitted with an ICC. How many drivers have had what experience? (quantitative: numbers). Altogether 76 of the 137 survey forms were returned. 3. Interviews (by telephone or by completing a questionnaire by email) with car dealers and sales staff provided information about what sales people think of these systems and the way in which they introduce them to their clients. Ten dealers altogether were approached by telephone and by e-mail and five took part in the study. (Author/publisher)
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