Citation

Mussa R. J. Transp. Res. Forum 2004; 43(2): 117-127.

Copyright

(Copyright © 2004, Transportation Research Forum)

DOI

unavailable

PMID

unavailable

Abstract

Trucks are restricted from using the median lane of the six-lane Interstate 75 freeway corridor in north Florida. This study seeks to determine the operational and safety impacts of this 24-hour-a-day restriction. The 139-mile corridor is relatively uncongested, operating at level of service of B or better on typical weekdays. The simulation analysis indicated that opening all lanes to trucks increased the number of lane changing maneuvers by 11% in daytime, a phenomenon likely to increase crashes in the corridor given that the review of reported crashes showed that lane changing was a major contributing cause of crashes currently occurring in the corridor. The analysis of field data indicated that the difference between truck and passenger car speeds and travel times were insignificant on the unrestricted middle and shoulder lanes. Approximately two-thirds of both passenger cars and trucks were traveling within the 10-mph pace, defined as the 10-mph speed range with the highest number of observations, that ranged from approximately 70 mph to 80 mph in the corridor that has speed limit posted at 70 mph. The field data also showed that trucks were able to use the middle lane to pass with reasonable delay during the truck peak hour period, using various gap acceptance thresholds. Overall, these results suggest that the policy might be offering safety benefits, and that there is not much to be gained for trucks or passenger cars if the lane restriction is rescinded.