Three Player Interactions in Urban Settings: Design Challenges for Autonomous Vehicles

An observational analysis of crossing episodes between two intersecting vehicles, in which a third road user clearly affected its evolution, was conducted in an attempt to identify (i) recurring patterns of informal coordination among road users and (ii) traffic situational invariances that may inform AV prediction algorithms. The term BLOCK-EXPLOITING is introduced to describe a driver’s exploitation of situational opportunities to gain priority often contrary to regulatory provisions, but favouring overall traffic efficiency. Video-data from an urban stop-controlled intersection were analysed through the lens of joint systems theory using a phenomenological framework developed in this study. Four generic types of BLOCK-EXPLOITING were identified (i.e. covering, ghost-covering, piggybacking, sneaking). Covering and ghost-covering led to minimal or no delays while piggybacking and sneaking, although abusive to other drivers, still only resulted in 1.99 to 3.33 sec delay. It is advocated that BLOCK-EXPLOITING can be socially acceptable. Proposed design challenges for AVs in mixed traffic include the ability to (i) distinguish BLOCK-EXPLOITING from errant driving, (ii) recognise to whom a ‘space-offering’ is addressed, and (iii) assess the appropriateness or abusiveness of a BLOCK-EXPLOITING action. Finally, this study brings to fore very short-time span joint-activity coordination requirements among diverse agents unknown to each other.