940.7 Median Opening Spacing

From Engineering Policy Guide

Jump to: navigation, search

Openings in raised medians are only to accommodate turning traffic in locations where this can be safely done. Where openings are provided, an adequate spacing between them is necessary to allow for weaving of traffic to preserve traffic flow and provide for safe lane changes and turns.

A full opening allows turns to be made in both directions; a directional opening allows turns to be made in only one direction. An example of a directional median would be one that allows left turns into a driveway but does not allow left turns to be made out.

Distances between Directional Median Openings
Distances between Directional Median Openings

Median openings are not to be allowed under the following circumstances:

  • On interstates or other freeways
  • Within the functional area of an interchange
  • Within the functional area of an intersection between two public roads
  • At locations that have high accident rates

Under conditions of inadequate sight distance, median openings shall not be allowed.

Traffic studies are to support the required length of queue storage for major traffic generators such as a shopping mall or industrial plant. For additional guidance on left turn queue storage see

In cases where left turns are restricted by lack of median openings, safe U-turns must be allowed. U-turns can be safely accommodated through a variety of means, including signal phasing and timing, widening and including physical design features such as turning lanes and “jug handles.” U-turns are to be prohibited if they cannot be made safely. U-turn opportunities are to be designed with an appropriate typical design vehicle.

Table 940.7 Spacing Between Median Openings to Accommodate Safe U-Turns Minimum Guidelines
Roadway Classification In Current and Projected Urban AreasIn Rural Areas
Major, Freeway No median openings allowed No median openings allowed
Major, Non-Freeway 1,320 to 2,640 ft.(full), 660 to 1320 ft.(directional) 1320 to 2640 ft. (spacing is to increase with higher posted speed)
Minor 1,320 ft.(full), 660 ft. (directional) Generally not applicable
Personal tools