A capacity‐increasing mechanism in freeway traffic

A reason is unveiled for the time‐varying pattern in discharge flow that is commonly observed at freeway bottlenecks. We hypothesize that four known effects in freeway traffic can interact upstream of a bottleneck in ways that trigger periodic bursts in its discharge flow. Repeated observations of a 3‐km freeway stretch support the hypothesis. Controlled experiments show that the capacity‐increasing mechanism can be favorably modulated by metering the site’s on‐ramps in an unconventional manner. The unconventional strategy repeatedly produced higher average discharge flows and shorter on‐ramp queues than did a more traditional metering policy.