Summary

This project will test the effectiveness of on-ramp metering in reducing commuter delay "corridor-wide," meaning on- and off-ramps included. The study will be conducted on northbound I-5 in Sacramento from Pocket Road to W Street. The site of interest includes a number of bottlenecks, including one formed by a horizontal curve and other smaller ones created by on-ramp junctions. The intent is to collect data including discharge flows from all active bottlenecks and the exit flows at all off-ramps and from the downstream end of the freeway site.

The project will be conducted in the following manner: 1) bottlenecks will be verified by measuring vehicle arrival times at multiple fixed locations in their vicinities, 2) off-ramp flows will be measured using video cameras to quantify the favorable effects of metering on "gridlock-causing" queues, 3) details of the capacity drop mechanism will be identified at all bottlenecks by processing video data including time-series data of vehicle accumulations; from this, modifications can be made to the metering strategy, and 4) a final report detailing the aspects of the study will be prepared (including performance measures) and submitted to Caltrans.

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