The main public transportation service in Phnom Penh, the capital city of Cambodia, is motorcycle taxi (motodup) that is believed to be one of the main factors contributing to traffic congestion in the city. Bus service is available from the capital city of Phnom Penh to other provinces only which are very inconvenient as a public transportation service. Therefore, city bus service, which is believed to be an effective transportation service as well as a sustainable transportation planning, will play an important role in decreasing the amount of traffic congestion. Moreover, bus service is...