Date of this Version
Report #: SPR-P1(06) P592 Final Report WBS# 26-118-0083-001
Many transportation agencies have started using offset right-turn lanes (ORTLs) at two-way stop-controlled intersections in the hope of improving driver safety by providing intersection departure sight distance triangles that eliminate through roadway right-turning vehicle obstructions. Currently, there are no specific geometric guidelines for key three-dimensional characteristics to allow drivers the optimal use of laterally-shifted right-turn lanes. Results of driver behavior studies at existing locations of offset right-turns lanes indicate that drivers are not performing as expected at parallel-type ORTLs, rendering its presence useless. Tapered-type ORTLs appear to be much more intuitive to driver expectancy and appropriate for the three-dimensional characteristics of all vehicle types. This research project identifies specific negative driver behaviors and recommends appropriate traffic control devices that meet current MUTCD guidelines to mitigate misleading visual cues and accentuate elements that reinforce the intended positive behavior at ORTL intersections for successful use of the laterally-offset right-turn auxiliary lane.