Real-Time Level of Service for Signalized Urban Intersections Based on Vehicle-To-Everything Communication

Level of Service (LOS) is a metric that assesses the capacity and quality of traffic flow in a road or transportation system. It takes into account factors like speed, traffic density, delays, and driver comfort, and assigns them various levels to determine the level of traffic congestion or improvement. Different definitions of LOS are used for designing and planning, such as the widely used Highway Capacity Manual (HCM) or the German Handbuch zur Bemessung von Straßenanlagen (HBS). Realtime monitoring of LOS typically relies on detection infrastructure like loops or aerial monitoring, but both methods cannot be continuously employed in time and space.
In this paper, we propose an online LOS monitoring service based on Vehicle-to-Everything (V2X) communication. We rely on the fact that connected mobility is becoming a reality, with more and more connected infrastructure available (through EU-project C-Roads and others) and connected vehicles on the street (mainly the Volkswagen brand). We use the Cooperative Awareness Message (CAM), which provides basic information about the position and dynamics of the vehicle, to generate Origin-Destination relations as well as determining queue length and delay.This information is combined with phase state information provided by the connected infrastructure using Signal Phase and Timing (SPAT) messages. The advantage of this approach is that only one V2X-receiver is required for monitoring. We will provide a description of the system as well as measurement results from an existing intersection.