Yogyakarta is a small city at the middle-south of Java Island. As the city of tourism, education, and culture Yogyakarta has been the destination for the other regions, not only in Indonesia but also abroad. Good accessibility has enabled Yogyakarta to develop rapidly. The tendency nowadays shows that Yogyakarta, population 510 108 (Yogyakarta In Figures, 2003), is conglomerating to form an urban area with a population of more than 1 million. This is increasing the ctiy's service costs, including especially transportation services.
Transportation in Yogyakarta is mixed traffic, in which all types of vehicles run on one road. The mixed traffic condition thus results in chaotic traffic. Streets jam as the traffic volume overloads road capacity. Human-powered vehicles and motorcycles, which are almost 80% of the total traffic volume, dominate the roads in Yogyakarta.
Figure 1. Bikes, motorbikes, cars, everything, using the same lane