ROAD USERS' OPINION ON VARIABLE SPEED LIMITS - A DRIVER INTERVIEW ON MAIN ROAD 9

A variable speed limit system was utilised on highway 9 on the 34 km stretch between Tampere (Alasjarvi) and Orivesi on 5.1.2000. The system consists of 26 variable speed limit signs controlled mainly according to weather and road conditions. The road section has a 4 km long motor-traffic way at the Tampere end and the rest is ordinary mixed traffic road. The traffic flow (1998) was 6 900-14 400 vehicles daily. The signs are controlled mainly according to weather and road conditions. The signs can also be controlled in special cases e.g. roadwork, accidents or congestions. The weather and road condition classes are equivalent to ones in the road weather bulletins. For the line road sections the speed limit used for normal road conditions is 100 kmph, 80 kmph for bad and 70 kmph for really bad road conditions. At junctions the corresponding speed limits are 80, 70 and 60 kmph. However, from November to February the maximum speed limit during the hours of darkness is 80 kmph. The speed limit for really bad road conditions was not used at all during the spring of 2000. Driver opinions about the system were studied by roadside interviews two months after the installation of the system. 457 drivers of light and 93 drivers of heavy vehicles were interviewed during two days. About half of the drivers had driven on the road section weekly or more often after the utilisation of the system. Most of the drivers knew that the speed limits were variable. The knowledge clearly declined with age. Most knew that the speed limits were controlled according to road and weather conditions, over half of the people did not, however, know that the data was gathered automatically. In addition to this 11-16% believed that the speed limits were controlled also by traffic situations. Most of the drivers of both light and heavy vehicles supported the 80 kmph speed limit for the road in bad road conditions in daylight. The opinions for a suitable speed limit in good road conditions during the hours of darkness were almost equally divided 80 kmph and 100 kmph. The system was mostly said to increase safety or traffic flow and speed limits were seen to match the real situation. The drivers of light vehicles thought more positively of the system than those of heavy vehicles. The drivers deem the variable speed limits necessary and trust greatly that the speed limits used are appropriate to the conditions. Although the system is controlled by hand almost all drivers thought that the speed limits were always or mostly correctly set. The maintaining of this trust thus sets high quality requirements for the operation of the system and control of the signs in all driving conditions including incidents. The study has been granted European Community financial support in the field of Trans-European Networks - Transport.