  Semi-cooperative behaviors are intrinsic properties of human drivers and
should be considered for autonomous driving. In addition, new autonomous
planners can consider the social value orientation (SVO) of human drivers to
generate socially-compliant trajectories. Yet the overall impact on traffic
flow for this new class of planners remain to be understood. In this work, we
present study of implicit semi-cooperative driving where agents deploy a
game-theoretic version of iterative best response assuming knowledge of the
SVOs of other agents. We simulate nominal traffic flow and investigate whether
the proportion of prosocial agents on the road impact individual or system-wide
driving performance. Experiments show that the proportion of prosocial agents
has a minor impact on overall traffic flow and that benefits of
semi-cooperation disproportionally affect egoistic and high-speed drivers.
