Knowledge Resources

This study used simulation techniques to evaluate the impacts of ITS on the John C. Lodge freeway in Detroit, Michigan. The study was able to discount freeway bias (driver preference for freeways) and analyze the system and facility level benefits of ITS currently deployed in the corridor.

ITS in the corridor consisted of internet-based pre-trip advanced traveler information systems (ATIS), highway advisory radio (HAR), ramp metering, and dynamic message signs (DMS). The performance of these systems was analyzed through a series of simulations that evaluated four alternatives:

• No-ITS.
• Ramp metering.
• Variable message signs.
• Existing-ITS (ATIS, HAR, ramp metering, and DMS).

The INTEGRATION simulation model was used to generate peak PM arterial and freeway corridor conditions for roughly 40,000 to 50,000 vehicles per hour during 80 different scenarios of impedance (varied weather, incident patterns, etc.). The model was calibrated using flow and speed data derived from field observations.

RESULTS

Results from simulation testing indicated the existing ITS systems were beneficial to corridor capacity. Ramp metering was most effective at reducing congestion during major incidents, however, the study questioned its use in the absence of incidents or during minor incidents.