Taper Length Calculator for Work Zone Lane Closures
Getting taper length right is one of the most important — and most commonly miscalculated — parts of a lane closure. This guide explains how taper length is determined and how to calculate it correctly for your work zone.
What is a merging taper?
A merging taper is the section of a work zone where traffic is guided out of a closed lane. Its length depends on the posted speed limit and the width of the lateral shift. Too short a taper forces abrupt, dangerous merges; too long wastes devices and space. The MUTCD provides formulas to size it correctly.
How taper length is calculated
For speeds of 45 mph or higher, taper length L equals the speed (S) multiplied by the lane width offset (W): L = S × W. For speeds of 40 mph or lower, the formula is L = (S² × W) ÷ 60. Once you have the taper length, channelizing devices are spaced along it at intervals based on the posted speed.
Let the software do the math
Traffic Planner Pro applies the correct MUTCD taper formula automatically based on your speed and lane configuration, then places the right number of channelizing devices at compliant spacing. You get an accurate taper every time — no manual lookup, no arithmetic errors.