2019/01/16 by Negar Mehr, Mehr, Negar, Roberto Horowitz +1
Social Sciences · Engineering · #Transportation Planning and Optimization #Traffic control and management #Transportation and Mobility Innovations
paper · pdf · doi:10.48550/arxiv.1901.05168
It is known that connected and autonomous vehicles are capable of maintaining\nshorter headways and distances when they form platoons of vehicles. Thus, such\ntechnologies can result in increases in the capacities of traffic networks.\nConsequently, it is envisioned that their deployment will boost the network\nmobility. In this paper, we verify the validity of this impact under selfish\nrouting behavior of drivers in traffic networks with mixed autonomy, i.e.\ntraffic networks with both regular and autonomous vehicles. We consider a\nnonatomic routing game on a network with inelastic (fixed) demands for the set\nof network O/D pairs, and study how replacing a fraction of regular vehicles by\nautonomous vehicles will affect the mobility of the network. Using the well\nknown US bureau of public roads (BPR) traffic delay models, we show that the\nresulting Wardrop equilibrium is not necessarily unique even in its weak sense\nfor networks with mixed autonomy. We state the conditions under which the total\nnetwork delay is guaranteed not to increase as a result of autonomy increase.\nHowever, we show that when these conditions do not hold, counter intuitive\nbehaviors may occur: the total delay can grow by increasing the network\nautonomy. In particular, we prove that for networks with a single O/D pair, if\nthe road degrees of asymmetry are homogeneous, the total delay is 1) unique,\nand 2) a nonincreasing continuous function of network autonomy fraction. We\nshow that for heterogeneous degrees of asymmetry, the total delay is not\nunique, and it can further grow with autonomy increase. We demonstrate that\nsimilar behaviors may be observed in networks with multiple O/D pairs. We\nfurther bound such performance degradations due to the introduction of autonomy\nin homogeneous networks.\n