  In this paper we study a traffic intersection with vehicle-actuated traffic
signal control. Traffic lights stay green until all lanes within a group are
emptied. Assuming general renewal arrival processes, we derive exact limiting
distributions of the delays under Heavy Traffic (HT) conditions. Furthermore,
we derive the Light Traffic (LT) limit of the mean delays for intersections
with Poisson arrivals, and develop a heuristic adaptation of this limit to
capture the LT behaviour for other interarrival-time distributions. We combine
the LT and HT results to develop closed-form approximations for the mean delays
of vehicles in each lane. These closed-form approximations are quite accurate,
very insightful and simple to implement.
