Chapter 7 - At Grade Intersections

7.3. Median Openings

For design policies concerning median cross sectional elements, refer to Chapter 6. Cross Section Elements, Section 6.8. Medians, of this Manual.

Medians separating opposite direction travel lanes shall be installed for the primary purpose of ensuring the safe, efficient movement of traffic. The introduction of median openings increases the driving hazard and also impedes the smooth flow of traffic, thus reducing the safety and capacity of highways.

The following guidelines shall be strictly followed when allowing median crossovers, as well as when requests are received for additional crossovers on completed roadway sections:

• Median Crossovers should not typically be installed or permitted to serve a particular development; however, when it can be documented that such an installation will benefit the overall safety, traffic flow and efficiency of the roadway, consideration will be given to installing a median opening. Priority will be given to establishing crossovers at existing roads and streets before other locations.

• GDOT prefers full median openings to be spaced at 1,000-ft in urban areas. However, median openings may be spaced less than 1,000-ft, and greater than 660-ft, in urban areas if there are minimal left turn volumes.  Median openings shall be spaced at 1320-ft. in rural areas.  For all other intersections spacings greater than the minimum specified median openings must be determined based on taper, deceleration, and storage lengths based on traffic volumes.

• The maximum spacing between median crossovers in developed areas (including single occupied residence) should be one mile. In areas without any development or where there are no driveways due to access control, the maximum spacing between crossovers should be 2 miles. In urban areas a practical maximum spacing between crossovers is approximately ½ mile. Since it is desirable to place crossovers only at local roads, the crossover may be shifted slightly to line up with an existing road or major traffic generator.

• Median crossovers for new and reconstructed facilities shall be constructed in accordance with GDOT Construction Standards and Details,  Construction Detail M-3, Type A, B, or C. Type B crossovers are preferred and should be used where drainage can be adequately designed and speeds are greater than or equal to 55 mph. Consideration for use of Type B crossovers should also be given when engineering judgment dictates that the design is practical in median widths less than 32-ft. and when there are more than two approach through lanes.

• For 6 lane roadways, full median breaks shall be granted only at signalized intersections. 

• For four-lane, divided projects with less than 32-ft. of median width, additional pavement width (i.e., eyebrow) to facilitate U-turn movements shall be provided as part of the crossover construction.  However, depending on traffic type using the facility additional pavement  for U-turns shall be verified with appropriate turning paths, may require truck turn-around ramps  (i.e., jug handles).   Refer to the GDOT Construction Standards and Details, Construction Detail M-3, Type C Median Crossover.

• Deceleration lanes will be provided at all crossovers.

• Adequate sight distance shall be available for any location where crossover is allowed.

• The designer shall refer to the National Cooperative Highway Research Program (NCHRP) report, Safety of U-Turns at Unsignalized Median Openings (Report 524), when designing intersections with U-turn capability.