1998 Volume 11 Issue 3 Pages 120-126
Today, many automobile traffic jams always occur on expressways. A traffic jam burdens drivers with congestion, and causes air pollution. In order to avoid a traffic jam, the traffic information should be offered. Ordinary method which detects the traffic jam requires many traffic detectors on the roads, but these systems are very large and expensive to construct. By using the characteristic lines method, it is possible to estimate the traffic density between two detecting points. This method can be applied on condition that the property of road is uniform, but the property of practical road is not uniform. There are some bottleneck points like tunnels that cause traffic jams. This paper reports the method that determines the change of traffic density at the entrance of bottleneck. As a result, the characteristic lines method is also useful on the long road which includes a bottleneck section.