  Connected and automated vehicles (CAVs) and human-driven vehicles (HVs) are
expected to coexist in the near future. CAV-dedicated lanes and phases have
been explored to handle the uncertainty in the driving behavior of HVs in the
mixed traffic environment. However, CAV-dedicated phases could significantly
sacrifice HV benefits. This study proposes a shared-phase-dedicated-lane
(SPDL)-based traffic control model at isolated intersections under the mixed
traffic environment. Left-turn and through CAVs share CAV-dedicated lanes and
cross the intersection during the shared phases with HVs. A three-level
optimization model is developed. At the upper level, a standard NEMA (National
Electrical Manufacturers Association) ring barrier structure is used for the
signal optimization and barrier durations are optimized by dynamic programming
to minimize the total vehicle delay. At the middle level, phase sequence and
phase durations are optimized by enumeration for the given barrier from the
upper level and the minimum vehicle delay is fed to the upper level. At the
lower level, CAV platooning in the buffer zone and trajectory planning in the
passing zone are conducted based on the signal timings of the barrier from the
middle level and the travel time of CAVs is fed to the middle level. A
rolling-horizon scheme is further designed for the dynamical implementation of
the proposed model with time-varying traffic conditions. Numerical studies
validate the advantages of the SPDL-based control over the blue-phase based
control in previous studies in terms of average vehicle delay and intersection
capacity. Further, the SPDL-based model is extended to serve as an alternative
approach without the buffer zone.
