Combined flexible lane assignment and reservation-based intersection control in field-like traffic conditions

A concept called Combined Alternate-Direction Lane Assignment and Reservation-based Intersection Control (CADLARIC) was recently proposed for better management of directionally unrestricted traffic flows in a Connected and Autonomous Vehicles (CAVs) environment. In CADLARIC, vehicles must position themselves in a proper lane before they reach the downstream intersection, which enables the resolution of vehicular conflicts both between intersections and, as traditionally, within the intersection boxes. CADLARIC has shown very promising results, but it is quite infrastructurally demanding, requiring six lanes per intersection approach. To overcome this problem, we propose here Combined Flexible Lane Assignment and Reservation-based Intersection Control (CFLARIC), a more robust concept that offers a full spectrum of lane assignment possibilities in combination with the appropriate reservation-based intersection control. Three distinctive CFLARIC strategies are tested on a simulated three-intersection corridor from West Valley City, Utah. The efficiency and safety performance of the proposed CFLARIC scenarios are evaluated through a comparison with Fixed-Time Control (FTC) and Full Reservation-based Intersection Control (FRIC), both with conventional lane assignments. The results illustrate that CFLARIC scenarios: (i) outperform FTC and FRIC in terms of efficiency (delay and number of stops), and (ii) improve overall safety (by reducing a number of conflicting situations) when compared to FRIC. The findings of this study prove that flexible control concepts such as CFLARIC have a great potential to improve safety and efficiency in future CAV environment. Future research needs to define under which conditions and how the proposed concept could be partially implemented in field operations.