Automobile and Motorcycle Traffic on Indonesian National Roads: Is It Local or Beyond the City Boundary?

This paper investigates the dimensions of private vehicles’ trips on national roads between neighboring cities in Indonesia using the spatial lag model and the spatial error model approach to reveal the spatial correlations among cities. Private vehicles are defined as privately owned automobiles and motorcycles, and vehicle trips or usage levels are defined in terms of vehicle kilometers traveled (VKT) for both types of private vehicles. The paper finds that motorcycle trips are characteristically local because there is no sign of a spatial correlation with neighboring cities for those trips; by contrast, automobile trips often cross city boundaries, although the models constructed in this study demonstrate only weak spatial correlations among neighboring cities for automobile trips. The models also indicate that the road capacity, gasoline prices, gross domestic regional product per capita, population density, city size, number of public buses, and worker resident density have a significant effect on VKT for both cars and motorcycles. Therefore, these findings suggest that in general, the design of urban transportation policies on national roads could be less complex in Indonesian cities because local solutions may be effective for solving traffic problems in individual cities.