I. Introduction
The last three decades have seen steadily increasing research efforts, both in academia and in industry, towards developing driverless vehicle technology. These developments have been fueled by recent advances in sensing and computing technology together with the potential transformative impact on automotive transportation and the perceived societal benefit: In 2014 there were 32 675 traffic related fatalities, 2.3 million injuries, and 6.1 million reported collisions [1]. Of these, an estimated 94% are attributed to driver error with 31% involving legally intoxicated drivers, and 10% from distracted drivers [2]. Autonomous vehicles have the potential to dramatically reduce the contribution of driver error and negligence as the cause of vehicle collisions. They will also provide a means of personal mobility to people who are unable to drive due to physical or visual disability. Finally, for the 86% of the US work force that commutes by car, on average 25 minutes (one way) each day [3], autonomous vehicles would facilitate more productive use of the transit time, or simply reduce the measurable ill effects of driving stress [4].