Lane Widths, Channelized Right Turn and Right Turn Deceleration Lanes

• Published by:  Midwest Research Institute

NCHRP Project 03-72, “Lane Widths, Channelized Right Turn and Right Turn Deceleration Lanes in Urban and Suburban Areas,” Active TRB Project.
The Midwest Research Institute (MRI) submitted the draft final report for NCHRP 03-72 in August of 2006, but at this time it has not been published. The project PI provided theAMM2 team a copy of the draft final report as well as a synthesis on right-turn deceleration lanes and one on channelized right turn lanes at intersections on urban and suburban arterials. As part of this research effort, the MRI team proposed a variety of study elements at the interim report phase of the project in addition to the syntheses previously indicated. Following this review the project team performed a field study and an empirical analysis on lane widths as well as an operational and safety study for motor vehicles and pedestrians at right-turn lanes. The channelized right turn focus was determined to be beyond the project budget and was not selected for additional evaluation following panel review of the interim report. The right-turn deceleration lane study resulted in the following findings:

• For two-lane arterial locations, the estimated reduction in delay as a result of adding a right-turn deceleration lane ranges from 0 to 6 seconds per through vehicle.
• For four-lane arterial locations, the estimated reduction in delay associated with the right-turn deceleration lane is much less at 0 to 1 seconds per vehicle.
• Pedestrians interacting with unsignalized driveways or intersections can create substantial delay, and so the use of a right-turn deceleration lane can result in reduced delays of 0.4 to 2.1 seconds per through vehicle for locations with 50 pedestrians per hour. At locations with 100 pedestrians per hour, the expected delay reduction benefits can range from 0.6 to 3.1 seconds per through vehicle.
• The MRI team developed an economic analysis method that can be used to help agencies determine when it is most cost-effective to include a right-turn lane at intersections and major driveways.