Refinement of Performance Measures based on High-Resolution Signal and Detection Data

Most previous evaluation studies of various signal control strategies, both in the field and through microsimulation, used common traffic performance measures (PMs) related to travel times, number of stops, control delay, etc.. Recent advancements in detection and controller data-logging capabilities have brought forth new types of signal PMs. Two such measures known as Arrivals on Green (AOG) and Approach Delay (AD) have been recently used in a number of projects by other universities and state departments of transportation. A study that evaluated InSync through these high-resolution PMs showed that AOG, as a single PM, cannot be fully trusted when comparing traffic signal alternatives, as it does not reflect the efficiency of the allocated green time used by an arriving platoon of vehicles. The findings also suggested that currently used methodologies underestimate AD, as they simplify their computation. This study proposes development of a new high-resolution PM - Average Arrivals on Green Ratio (AAOGR) that takes into account variability of cycle length and green time, on a cycle-by-cycle basis (thus applicable for dynamic control) and provides information on the ratio of vehicles that passed through the intersection per a second of green time. Moreover, a discharge rate-based model for computing AD, which takes into consideration the possible queue build-up during red and provides better estimation of true AD per vehicle if measured in front of the advanced detectors, is proposed as well.