Abstract
Traffic regulations mandate the use of winter tires in the interests of smooth traffic flow during heavy snow days. In this situation, road administrators must visually inspect vehicles to ensure summer tires are not being used on expressways. However misjudgment is unavoidable only by visual inspection and heavy traffic jams eventually occur. To avoid such traffic jams, an automatic tire discrimination system is required. In this report, we propose a simple method of discrimination between summer and winter tires using tire/road noises emitted by running vehicles, and evaluate the relationship between road surface roughness and the impact noise patterns of winter tires. Additionally, we consider the influence of road surface conditions such as dry and wet surfaces on the proposed discrimination method. Finally, we confirm the effectiveness of the discrimination system in the field using a number of vehicles with different tires.