What is the minimum length for shoulder taper according to traffic control standards?

The minimum length for a shoulder taper is defined as 1/3 of the length of the lane being closed, which is the reason this answer is correct. The concept behind this standard is to provide a gradual transition that allows vehicles to smoothly move from the travel lane onto the shoulder. This taper length is designed to enhance safety by minimizing the risk of abrupt maneuvering or lane change requirements, thereby reducing potential accidents and ensuring that drivers have ample time to adjust to changing road conditions.

The traffic control standards specify this taper length to ensure uniformity and effectiveness across various roadway scenarios. Proper taper lengths facilitate the flow of traffic and diminishes confusion among drivers faced with lane closures. Thus, adopting a minimum taper length of 1/3 L creates a predictable environment as vehicles approach the area of work or closure.

Other lengths provided in the options would not align with the standards set out for safe traffic management, emphasizing why they are not suitable. A taper that is too short would not provide enough distance for vehicles to adjust safely, and a taper that is excessively long could be impractical in many settings.