Studies to Determine the Effectiveness of Longitudinal Channelizing Devices in Work Zones

摘要

This report describes the methodology and results of analyses performed to determine whether the following longitudinal channelizing device (LCD) applications improve the traffic safety and operations of work zones relative to the use of standard drums: (1) Continuous LCDs in the vicinity of exit ramps on high-speed, limited-access facilities; (2) Continuous LCDs in the merging taper of a lane closure on low-speed roadways; (3) Single LCDs (similar to Type 3 barricades) in the merging taper of a lane closure on high-speed roadways; (4) Continuous LCDs in the vicinity of driveways on low-speed urban roadways. Based on the research findings, researchers recommended the use of continuous LCDs in the immediate vicinity of an exit ramp within a lane closure under the following conditions: (1) When a high number of deliberate intrusions into the work zone are expected or occur while using standard channelizing devices; (2) In situations where the exit ramp opening (in feet) is less than or equal to two times the posted speed limit (in mph), workers and equipment are in the work area near the exit ramp opening, and there are concerns that drivers may unintentionally enter the work area trying to access the exit ramp. Recommendations regarding the minimum exit ramp opening length within a work zone lane closure and the use of a closer drum spacing in the immediate vicinity of exit ramps are also discussed. Researchers do not recommend the use of continuous LCDs or single barricade style LCDs to form a lane closure merging taper. While continuous LCDs may also be used to delineate the edge of a travel lane in a work zone on an urban roadway, the height and location of the LCDs should be considered since they impact the ability of drivers to view approaching traffic. Researchers also discuss LCD delineation and other implementation considerations.