Framework for Evaluating Advance-Detection Designs for High-Speed Intersection Approaches

Abstract

This paper describes a framework for evaluating an advance-detection design. The framework can be used to identify the most effective configurations for a given detection design. It accounts for the detection layout, including number and position of detectors; traffic conditions, including volume and speed; and controller settings, including passage time and operation of the stop line detector after queue clearance. The framework is demonstrated by application to six advance-detection designs used in Texas. The framework is based on measures of control delay, probability of ending the green phase through max-out, and probability of providing indecision-zone protection during green-phase gap-out. The latter measure is defined as “detection coverage.” These measures are useful for quantifying the operational and safety performance of a detection design. The framework can be used (a) to select an advance-detection design for an intersection approach with a given 85th percentile traffic speed and (b) to determine the range of traffic speeds for which the detection design can provide acceptable indecision-zone coverage. This information is useful for sites where traffic speeds are not known precisely or are expected to vary over the day, week, or month. It can also be used to determine how changes in controller settings will affect the performance of the detection design.