Merging Taper Lengths for Short Duration Lane Closures

摘要

The Utility Industry has requested that the Florida Department of Transportation provide for the use of serging taper lengths that are significantly shorter than the lengths computed using the taper length equations published in the MUTCD Section 6C.08. This request pertains specifically to short duration lane closures of one hour or less in multilane urban areas where posted speeds are 45 mph or less. Shorter taper lengths allow for quicker installation and removal of traffic control devices, as well as reduced worker exposure time. The objective of the study were to (1) determine how the merging taper length affects the behavior of drivers approaching short duration work activities in the traveled way of multi-lane urban roadways with speed limits of 45 mph or less, and (2) develop recommendations regarding the use of shorter taper lengths for short duration work activities. Field studies were conducted in two separate phases. In phase I, merging taper lengths of 100 ft, 160 ft, and 540 ft were evaluated using standard DOT pickup trucks with typical warning lights and sequential flashing LED lightbars in the work area. In phase II, a no-taper condition, similar to a mobile operation, was evaluated using utility company bucket trucks, also with typical warning lights, but no lightbar, in the work area. Based on the study findings, researchers recommend that work operations that last more than 15 minutes utilize a merging taper length that meets MUTCD requirements. In addition, operations that last approximately 15 minutes or less can be accommodated as mobile operations without frequent operational or safety problems being created upstream of the work vehicle if certain conditions, which are documented in the report, are met.