Traffic congestion has large economic and social costs. The introduction of
autonomous vehicles can potentially reduce this congestion, both by increasing
network throughput and by enabling a social planner to incentivize users of
autonomous vehicles to take longer routes that can alleviate congestion on more
direct roads. We formalize the effects of altruistic autonomy on roads shared
between human drivers and autonomous vehicles. In this work, we develop a
formal model of road congestion on shared roads based on the fundamental
diagram of traffic. We consider a network of parallel roads and provide
algorithms that compute optimal equilibria that are robust to additional
unforeseen demand. We further plan for optimal routings when users have varying
degrees of altruism. We find that even with arbitrarily small altruism, total
latency can be unboundedly better than without altruism, and that the best
selfish equilibrium can be unboundedly better than the worst selfish
equilibrium. We validate our theoretical results through microscopic traffic
simulations and show average latency decrease of a factor of 4 from worst-case
selfish equilibrium to the optimal equilibrium when autonomous vehicles are
altruistic.Comment: Accepted to Workshop on the Algorithmic Foundations of Robotics
(WAFR) 201