Freeway On-Ramp Design Criteria for Ramp Meters with Excessive Queue Detectors

Guidelines were developed for designing freeway on-ramps in which ramp metering is envisioned. More specifically, design issues were probed for ramps in which the ramp meter utilizes a queue detector to identify and prevent a queue of vehicles from blocking the upstream intersection. First, the benefits of ramp metering operation were delineated, and general design considerations were then drawn up. Finally, design criteria were developed for three distance requirements for freeway on-ramps: safe stopping distance, storage distance, and acceleration distance.