Traffic Operations and Management

This report explores opportunities for employing autonomous driving technology to dampen stop-and-go waves on freeways. If successful, it could reduce fuel consumption and emissions. This technology was tested in an on-road experiment with 100 vehicles over one week. Public stakeholders were engaged to assess the planning effort and feasibility of taking the technology to the next level: a pilot involving 1000+ vehicles over several months. Considerations included the possible geographical boundaries, target fleets of vehicles, and suitable facilities such as bridges or managed lanes. Flow...

An effort was made to clarify certain issues concerning freeway onramp metering and its potential for saving commuter delay. Simple analogies were used to show that delay is reduced if ramp metering increases the rates at which commuters exit the freeway. Contrary to what is frequently reported in the literature, higher travel speeds and flows on links within a freeway system are not evidence of diminished delay and this too was made clear by the analogies. The discussion explains why a metering scheme should be specially tailored to the freeway it serves, and why no single metering logic...

Occupancies and flows were jointly sampled from numerous freeway segments in nearly stationary, unqueued traffic. The data from one segment were typically averaged across all lanes there and plotted. Each plot was compared with one sampled at a neighboring freeway segment, with the two segments differing only in their number of travel lanes. Such comparisons were repeated for a total of five pairs of segments on five freeways in and near Toronto, Canada and in California. All occupancy-flow relations were piece-wise linear in form for average flows up to about 2,000 vehicles per hour per...

This report summarizes a comprehensive research project directed toward the development and implementation of an Advanced Transportation Management and Information System (ATMIS) as part of the Caltrans Advanced ATMIS Testbed Program at the Institute of Transportation Studies, University of California, Irvine. The primary goal of this project was to implement this prototype ATMIS, designated TRICEPS (Testbed Realtime Integrated Control and Evaluation Prototype System), in the Irvine sub-area of the Advanced Testbed network. This sub-area represents a well-defined freeway corridor with a...