Estimating the Trip Generation Impacts of Autonomous Vehicles on Car Travel in Victoria, Australia

1 Autonomous vehicles (AVs) potentially increase vehicle travel by reducing travel and parking costs and by 2 providing improved mobility to those who are too young to drive or older people. The increase in vehicle travel 3 could be generated by both trip diversion from other modes and entirely new trips. Existing studies however tend 4 to overlook AVs’ impacts on entirely new trips. There is a need to develop a methodology for estimating possible 5 impacts of AVs on entirely new trips across all age groups. This paper explores the impacts of AVs on car trips 6 using a case study of Victoria, Australia. A new methodology for estimating entirely new trips associated with 7 AVs is proposed by measuring gaps in travel need at different life stages. Results show that AVs would increase 8 daily trips by 4.14% on average. The 76+ age group would have the largest increase of 18.5%, followed by the 9 18-24 age group and the 12-17 age group with 14.6% and 11.1% respectively. If car occupancy remains constant 10 in AV scenarios, entirely new trips and trip diversions from public transport and active modes would lead to a 11 7.31% increase in car trips. However increases in car travel are substantially magnified by reduced car occupancy 12 rates, a trend evidenced throughout the world. Car occupancy would need to increase by at least 5.3% to 7.3% to 13 keep car trips unchanged in AV scenarios. 14 15