At which speed should the taper length formula L=WS be used?

The taper length formula L = WS is critical for determining how to set up a safe and effective taper in a work zone or traffic control scenario. This formula is predicated on the speed at which vehicles are traveling, and for the formula to be applicable, it is primarily designed for higher speed roadways.

When considering the correct speed at which to apply this formula, 55 MPH is the optimal choice. At this speed, the taper length is calculated beyond the minimum requirements to ensure that drivers have adequate distance to notice the change in the roadway conditions, adjust their speed, and safely navigate through the taper. The taper serves as a transitional area where traffic moves from the normal roadway into a narrower or modified path, which is essential for maintaining safety and traffic flow.

The other choices, while they may involve some level of taper consideration, do not fully utilize the formula's design for taper lengths that accommodate higher velocity conditions. In lower speed zones, shorter tapers may suffice, and the dynamics of driver response differ compared to a 55 MPH roadway, emphasizing the importance of using the formula specifically at higher speeds to achieve effective taper lengths.