A general framework for modeling shared 1 autonomous vehicles

27 Shared autonomous vehicles (SAVs) could provide low-cost service to travelers and possibly 28 replace the need for personal vehicles. Previous studies found that each SAV could service 29 multiple travelers, thereby eliminating several personal vehicle trips. However, a major 30 limitation of previous studies is the reliance on custom software packages with unrealistic 31 congestion models, network structures, or travel demand. For effective comparisons with 32 personal vehicle scenarios, a common traffic flow simulator is necessary. 33 This paper presents an event-based framework for implementing SAV behavior in existing 34 traffic simulation models. We demonstrate this framework in a cell transmission model-based 35 dynamic network loading simulator. We also study a heuristic approach for dynamic ride36 sharing. We compared personal vehicles and SAV scenarios on the downtown Austin city 37 network. Without dynamic ride-sharing, the additional empty repositioning trips made by 38 SAVs increased congestion and travel times. However, dynamic ride-sharing resulted in 39