For speeds of 25 MPH, what is the recommended distance L for effective spacing?

The recommended distance L for effective spacing at speeds of 25 MPH is indeed 125 feet. This distance is established in traffic control guidelines to ensure that drivers are given adequate warning of conditions ahead. At lower speeds, such as 25 MPH, the time for drivers to react is shorter, so the spacing needs to be relatively close to allow for sufficient reaction time and to maintain safety.

Spacing relies on the principle that the distance to the traffic control devices should correlate with the speed of travel. At lower speeds, shorter distances are acceptable because drivers have a better ability to process and respond to the information provided by signs, cones, or other devices. This adaptation improves the effectiveness of the traffic control setup by minimizing confusion and encouraging compliance with traffic regulations.

Other distances provided in the options are typically applied to higher speeds, where extended distances are necessary to accommodate increased reaction times. For example, as the speed increases, the required distance for safe spacing also increases, reinforcing the relationship between speed and driver reaction time.