Impact of Detector Configuration on Performance Measurement and Signal Operations

Abstract

In recent years, automated traffic signal performance measures (ATSPMs) have emerged as a means of developing situational awareness of traffic conditions at intersections and assessing the quality of signal operations. As a growing number of agencies are adopting the technology, there is a need to understand how detector configurations can influence the outcomes of an analysis using ATSPM. Current practices with regard to detector configuration vary considerably from one agency to another; at one extreme, agencies may use one single detector input channel per phase without considering where the detectors are located, whereas at the other extreme, some agencies may utilize all possible channels to observe each individual lane at multiple positions. There are also variations in the design of detection zones (lengths and positions). This study takes on the problem in two parts. The first of these examines the impact of stop bar detection zone length and lane- or approach-based detector assignment on the ability of performance measures to identify accurately whether split failures occur. The second part examines the impact of setback detector distance on the use of a “percentage on green” metric that serves as a proxy measurement of the number of stops. The paper presents recommendations for performance measure calibrations and detector configurations that follow from these outcomes.

Development and Evaluation of Performance Measures for Capacity Utilization of Traffic Signals

“…The authors decided to comparatively evaluate SCATS DS and GOR , as a sidekick objective of this study, for two reasons: (1) to investigate previous claims that these two measures are the same, and (2) to explore GOR ’s performance in oversaturated conditions, considering that GOR was criticized in previous studies for its insensitivity to DS (e.g., its values flatten after moderate V/C and remain the same in saturated conditions) ( 7 , 21–23 ). Therefore, to investigate the full potential of both measures, an evaluation for a wide range of V/C values was carried out.…”

Assessment of Arterial Signal Timings Based on Various Operational Policies and Optimization Tools

“…To assess the performance of the developed signal timing plans on coordinated movements, both percentage (of arrivals) on green (POG) and travel times from the evaluated signal plans were compared. To collect POGs, advanced detectors were placed upstream from the stop bars based on recommendations from Emtenan and Day ( 29 ). POGs were extracted through the signal control detector records output file (.ldp) from Vissim.…”

Impact of Turning Lane Storage Length and Turning Proportions on Throughput at Oversaturated Signalized Intersections

“…Moreover, this work focused on one particular case study of a single intersection with protected left-turn phasing and no pedestrian interactions. The models developed here may not work well for adaptive or coordinated signal controls and factors like detector configurations or phase sequence can have impact on the models (28,29). Future work would seek to improve the proposed models through application to other field data with different scenarios to improve the transferability of the work and to develop factors that would allow the method to be more easily calibrated to any location and system.…”