How to determine the offset length, W, for Taper length calculations?

Professional Engineer & PE Exam Forum

Help Support Professional Engineer & PE Exam Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

new_at_this

Well-known member
Joined
Mar 19, 2018
Messages
93
Reaction score
39
Location
Orange County, CA
For temporary traffic control during construction, there are formulas to use to determine Taper length (for example, Taper length = W*S; where, W= Offset length, S = Posted speed limit).

My question is how you determine the offset length? Say, I am putting sign for working on a 12 ft wide lane; if I want to close that lane using traffic control signs, should I use offset length = 12 ft?

Please help me understand. 

 
W is the width of the lane or shoulder you are occupying...I’m not clear what exactly it is your asking for...for sign placement you have to go to the MUTCD they have plethora of Typical Details for various situations to determine how far apart the signs have to be... can you be more specific

 
The formulas are in the MUTCD on page 557. If the speed limit is 40mph or less, L=(WS^2)/60. If the speed limit is 45mph or greater, L=WS.

Then there's a table that gives further clarification based on the type of taper you have. For example, if it's a shifting taper, the minimum taper length is 0.5L.

 
Back
Top