Capacity Analysis of Traffic Flow Over a Single-Lane Automated Highway System⋆

Abstract

We calculate bounds on per-lane Automated Highway System (AHS) capacity as a function of vehicle capabilities and control system information structure. We assume that the AHS lane is dedicated for use by fully automated vehicles. Capacity is constrained by the minimum inter-vehicle separation necessary for safe operation. A methodology for deriving the safe minimum inter-vehicle separation for a particular safety criterion is presented. The inter-vehicle separation, which depends on the vehicle braking capability, control loop delays and operating speed, is then used to compute site-independent upper bounds on AHS capacity for a given mix of vehicle classes. The sensitivity of the capacity with respect to the degree of inter-vehicle cooperation, check-in policies (governing minimum acceptable vehicle-braking capability), highway speed limits, and lane-use policies (governing the sharing of a lane by multiple vehicle classes) is also investigated.