Lucy M. Richardson

Scalable Dashboard for Identifying Split Failures and Heuristic for Reallocating Split Times

The three fundamental parameters of a traffic signal system are split, cycle, and offset. This paper describes the use of high-resolution data (a) to identify time periods during which split parameters may be insufficient and (b) to help practitioners identify opportunities for reallocating split time. A case study of seven corridors with 47 intersections is presented. A drill-down approach was developed to identify movements that could be improved by a reallocation of split times. A heuristic that can reallocate up to 5 seconds of underutilized green time on a competing phase was applied to those corridors. For the selected phase identified in this study, the adjustment reduced split failures by an average of 40% while also decreasing yellow occupancy an average of 40% and red light violations an average of 66%. The paper concludes by recommending that central systems implement drill-down dashboards. Such tools would enable easy identification and systemwide monitoring of split failures and would provide opportunities to reallocate slack time.

Outcome Assessment of Peer-to-Peer Adaptive Control Adjacent to a National Park

In the town of Moab, Utah, a combination of seasonal tourist traffic, heavy truck traffic, and high pedestrian volumes creates a unique traffic management challenge; Moab’s remote location adds additional challenges for real-time traffic monitoring and maintaining of signal timing plans. The Main Street corridor is a strong candidate for an adaptive traffic control system (ATCS). Peer-to-peer (P2P) communication and user-definable control logic were used to develop and implement a cost-effective ATCS called “P2P adaptive control” that used only the existing local controllers and detection. The adaptive control logic adjusts green time along the mainline in response to detector inputs while keeping the side streets at the minimum time needed for pedestrian service. System performance was evaluated by comparing performance measures generated from high-resolution signal controller data before and after implementation of P2P adaptive control. The P2P adaptive control increased the through bandwidth of the corridor and reduced the number of split failures (i.e., the number of phase occurrences with insufficient green). Future work will include adjusting the algorithm to improve service on side streets and expanding P2P adaptive control to additional signals expected to be constructed in the area.