During the period may to September 1992 data about speeds on rural roads were collected 3 days per month in about 80 points all around Sweden. These points are chosen in order to be representative for traffic in rural areas in Sweden. At each of these points the number of cars, the number of lorries, the speed of cars and trucks are registrated continuously the whole year. To obtain good data-quality routines were changed a little during the 5 month period. Sensors and other equipment were controlled more frequently then before. Anyhow, the data from 2 points could not be used due to technical problems. At 5 of the point data was of low quality for 1 to 4 months. At the other points data could be used for 5 months. When looking at the cross~sections with the highest speed limit we find the following results for cars for straight and level roads: a) On motorways with a speed limit of 110 km/h the mean speed is measured to 109 km/h; b) On a two-lane road with a width of 13 m and speed limit 110 km/h the mean speed is measured to 104 km/h, and with speed limit 90 km/h, 97 km/h; c) For lorry without trailer we found 95, 91 and 87 km/h respectively; and d) For lorry and trailer we found 85, 83 and 81 km/h respectively. It ought to be mentioned that all these figures come from points with traffic flow below the flew where queues begin to reduce the speed. (A)
Abstract