Microsimulation of an autonomous taxi-system in Munich

Studies about autonomous taxis (aTaxis) concluded that empty vehicle movements account for a share of about 10% of vehicle miles traveled. In many of these studies, constant (in time or space) travel times are used due to a lack of data and to simplify the computations. Furthermore, the influence of the empty vehicle movements on the street network has not yet been a focal point of research. To address these two issues, the operation of an aTaxi system is implemented into an existing traffic microsimulation model. On the one hand, a microsimulation depicts travel times more accurately than constant link-level values. On the other hand, the taxi movements influence the flows along the network links and thereby have the potential to change travel times in the street network. Based on a calibrated Aimsun model of the city of Munich, a small number of scenarios are simulated: Starting from the calibrated OD matrix, a share of 10% of trips originating and ending inside the highway belt of Munich are completely or partially served by aTaxis. In case of a 1-to-1 substitution of private trips with aTaxi requests, the network-wide delay of private vehicles only increases by 1% due to induced empty rides. Furthermore, the differences between a simulation using linklevel travel times and a traffic microsimulation are studied. Delays due to left turns and traffic lights are present in the microsimulation. Results show, that fleet operation algorithms need to address these issues, which occur in reality.