Published in IET Intelligent Transport Systems Received on 1st April 2010 Revised on 22nd November 2010 doi: 10.1049/iet-its.2010.0041 ISSN 1751-956X Potential for in-car speed assistance systems: results of a large-scale survey in Belgium and the Netherlands S. Vlassenroot 1,2 V. Marchau 2 J. De Mol 1 K. Brookhuis 2,3 F. Witlox 4 1 Institute for Sustainable Mobility (IDM), Faculty of Engineering, Ghent University, Vrijdagmarkt 10/301 (AMRP), B-9000 Gent, Belgium 2 Section Transport Policy and Logistics’ Organisation (TLO), Faculty of Technology, Policy and Management, Delft University of Technology, Jaffalaan 5, 2628 BX Delft, The Netherlands 3 Department of Psychology, Faculty of Behavioural and Social Sciences, University of Groningen, Grote Kruisstraat 2/1, 9712 TS Groningen, The Netherlands 4 Department of Geography, Faculty of Sciences, Ghent University, Krijgslaan 281 S8, B-9000 Gent, Belgium E-mail: sven.vlassenroot@ugent.be Abstract: Speeding is generally considered to be a major cause of road traffic accidents. In-car speed assistance systems aim at reducing speeding. Several trials with different types of in-car speed assistance systems, in particular intelligent speed assistance (ISA), have shown that ISA can be an effective way to reduce speeding. A basic condition for achieving significant improvements in safety involves the adaptation of ISA among vehicle drivers on a large scale. This study focuses on the issue of acceptability of ISA. It is based on a large-scale survey of 6370 individuals in Belgium (Flanders region) and 1158 persons in the Netherlands. The respondents indicated that they believed that their own driving behaviour is of great influence on accidents and traffic safety, and that contextual issues like infrastructure or other drivers are less important. Almost 95% of the respondents are in favour of ISA: seven out of ten drivers state that they want to have some informative or warning system. Three out of ten drivers even wanted to go further; they indicated a preference for a restricting type of ISA. However, drivers would only choose for more restricting systems if the penetration rates of such systems in the vehicle market were high enough. 1 Introduction Advanced driver assistance systems (ADAS) involve in- vehicle systems that aim at improving vehicle-driving tasks. One of the most promising ADAS, aimed at reducing inappropriate speed, is intelligent speed assistance (ISA). ISA is an intelligent in-vehicle device that warns the driver about speeding, discourages the driver from speeding, and/ or prevents the driver from exceeding the speed limit [1–4]. Most ISA systems use global positioning system (GPS) and a digital speed limit database: the position of the vehicle is determined using a GPS-receiver. The position is used to retrieve the speed limit or other information from a database. The information is then reported to the driver. ISA can enforce three types of limits [4]: (i) static speed limits (posted speed signs), (ii) variable speed limits (spatially: information about speed limits depending on the location, e.g. lower speed around pedestrian crossings) and (iii) dynamic speed limits (in terms of time: information based on actual road and traffic conditions, e.g. reduced speed due to weather conditions). ISA-devices can be categorised into different types depending on much they intervene in the vehicle-driving task (or how the information is communicated to the driver). An informative or advisory system displays the recommended speed limit to remind the driver of the changes in speed levels. A warning or open system cautions the driver if the posted speed limit at a given location is exceeded; the driver then decides whether to use or ignore this information. An intervening, supportive or half-open system gives a force feedback through the gas pedal if the driver tries to exceed the speed limit [like the active accelerator pedal (AAP)]. It is however still possible for the driver to overrule the counter-pressure initiated by the accelerator pedal. A mandatory, automatic control, restrictive or closed system will fully prevent the driver from exceeding the speed limit; the driver cannot overrule the system. Several studies and field trials have indicated that ISA reduces speed and speeding [4–6]; that ISA is effective for traffic safety [4]; that ISA is expected to be beneficial for the environment because of the estimated reduction in speed and speed variance [7, 8]; and thus that ISA can lead to a more homogeneous traffic flow [9]. Although there has been no large-scale implementation of ISA, yet there have been promising initiatives in recent decades at European and national levels with respect to the development of technical feasibility frameworks (like geographical information storage, GPS-accuracy, vehicle communication etc.) and speed limit databases [10]. It could be generally concluded that at the European level the major technical guidelines and protocols for the feasibility and deployment of in-vehicle intelligent transport systems 80 IET Intell. Transp. Syst., 2011, Vol. 5, Iss. 1, pp. 80–89 & The Institution of Engineering and Technology 2011 doi: 10.1049/iet-its.2010.0041 www.ietdl.org