Taper Length Criteria for Work Zones

Roadway Tapers

The five types of roadway tapers (or transitions) used in work zone traffic control are the following:

  1. Merging Taper (L) - When a lane is closed and vehicles in that lane must merge with traffic in an adjacent lane.
  2. Shifting Taper (L/2) - When there is a lateral shift in the path of the lanes, but there is no reduction in the number of travel lanes.
  3. Shoulder Taper (L/3) - When the shoulder is closed to traffic.
  4. One-lane, Two-way Taper - When one lane of a two lane, two-way roadway is closed to traffic and where alternate one-way operation in one lane is in effect.
  5. Downstream Taper - When transitioning traffic back to the normal traveling conditions.

Table 1: Taper Lengths and Number of Cones Chart