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White Lane Drop Arrows

Status: Complete

Description: This study examined the effect of lane drop arrows on lane distributions, vehicle speeds, and vehicle conflicts at a long-term work zone in Missouri. The arrows were primarily intended to reduce traffic speeds, speed variability, and the percentage of vehicles in the closed lane. The data analysis examined the difference in the parameters before and after the lane drop arrows were installed. The primary measures of effectiveness were lane distributions, speed mean, and speed variance; however, other parameters were also studied for significance in the evaluation of the traffic control devices. For the before and after studies, the analysis took into consideration the effects of time of day and class of vehicle.

The lane drop arrows were associated with improved lane distributions at Sites 3 and 4 during the day. In general, the arrows were associated with improved mean, 85th percentile, and mean speeds of the fastest 15% of vehicles. The standard deviation of speed apparently improved in the daytime when the arrows were in place.

Report: MwSWZDI-2000-Sanford_Bernhardt-White_Lane_Drop_Arrows.pdf 1.7 mb (published 2000)

State conducting research: Missouri


  • Advanced Traffic Markings


  • Sanford Bernhardt, Kristen L. (University of Missouri, Columbia)
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