EFFECT OF STUDDED TIRES ON THE FLOW OF TRAFFIC

I: Study of the skid resisting properties of studded tires versus regular tires subject to dominant road conditions (pp. 1-49). The report discusses the problem and research methods and describes the actual research of measuring skid resisting properties of tires. It concludes that studded tires have a 15-20% (dry surface) or 17-26% (wet surface) longer brake path than regular tires on all surfaces. On poured asphalt, studded tires have a 40% longer brake path. These differences in length of brake path increase for the driver the danger of miscalculating the brake path and therefore increase the danger of accidents. (33 pp. of tables, figures, photos). II: Speed behavior of passenger cars with and without studded tires (pp. 51-72). The use of studded tires can wear out road surfaces 2.5 to 3 times faster than regular tires and therefore increase the cost of road maintenance enormously. The attrition of road surfaces also increases road accidents. Resutl: studded tires are extremely expensive to the total economy. This study is concerned with German drivers' responses to different speed limits for cars with studded tires (100km/h) and those with regular tires (no speed limits) and it concludes that the percentage of studded tires has already decreased since the public was informed of the dangers and costs involved in their use. III: Researching the direct influence of studded tires on accidents. III a): Driving performance of cars with studded tires 1970/1971. The percentage of cars with studded tires of the total number of cars was 17-32% in the 3 areas studied. Larger cars used studded tires more than small cars. Drivers on business used them more than others. Only 3-6% of all drivers used safety belts. III b): Accident percentage of cars with studded tires (pp. 115-147). Traffic percentage of cars with studded tires was 19.8-41.7% at the time of the study. Cars with studded tires had however 35-50% fewer accidents than those with regular tires.