U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

Skip to content U.S. Department of Transportation/Federal Highway AdministrationU.S. Department of Transportation/Federal Highway Administration

Bridges & Structures


Contact information was updated by Vertical Clearance Memo on 4/15/09.

Subject: ACTION: Vertical Clearance, Interstate System Coordination of Design Exceptions Date: September 17, 1999
From: /s/ Original signed by:
Henry H. Rentz
Director of Program Administration
Reply to Attn. of: HIPA
To: Resource Center Directors
Division Administrators
Program Manager, Federal Lands Highway

On August 15, 1997, the Associate Administrator for Program Development (now Program Manager, Infrastructure CBU) sent to the Regional Administrators and the Federal Lands Highway Program Administrator a memorandum concerning the policy and procedures for coordination of design exceptions to the vertical clearance standard on the Interstate system. The vertical clearance requirement for the Interstate System is contained in A Policy on Design Standards - Interstate System, AASHTO, 1991. The FHWA vertical clearance policy and coordination procedure are incorporated into the Federal-Aid Policy Guide, Non-regulatory Supplement, 23 CFR 625, paragraph 7. Briefly, all exceptions to the 4.9-meter vertical clearance standard for the rural Interstate and the single routing in urban areas are to be coordinated with the Military Traffic Management Command, Transportation Engineering Agency (MTMCTEA). The purpose of this memorandum is to remind all offices that the above policy and coordination requirements remain in effect.

Since August 1997, several inquiries have been received from field offices as to the status of this requirement and whether or not MTMCTEA is still interested in obtaining the 4.9-meter vertical clearance. The MTMCTEA has concurred with design exceptions at a number of locations where the structure fails to provide the required vertical clearance. The MTMCTEA evaluates each case individually, and concurrence is generally based on the following: a bypass or parallel route (with standard clearances) is available; the vertical clearance standard will be met with a future project; the increased costs associated with meeting the requirement are not practical; or the route in question currently does not have a direct impact on defense deployment.

We have confirmed that MTMCTEA still desires to continue the established procedures to ensure their awareness of these nonstandard clearances in the event a defense emergency arises. The military continues to have a need for the 4.9-meter clearance. The size of future equipment is unknown and there is a desire to retain options for any equipment developed in the future.

National security is one of FHWA's five Strategic Goals. As part of the implementation of this goal, FHWA is committed to improving the Nation's defense mobility by promoting the improvement of the condition, capacity, and operation of the highway system. Accordingly, FHWA should continue to coordinate with MTMCTEA and the State Departments of Transportation to achieve the vertical clearance requirements necessary to satisfy all agencies. The attached format or anything similar may be used for providing coordination information.


Interstate Vertical Clearance Exception Coordination

1. Structure Location:

Route Name:
Overpass Route:
Structure NBI Number:
___ Rural ___ Urban Single Routing

Include a map showing the general vicinity

2. Project Description:

Estimated Total Project Cost: $

3. Description and Location of the substandard clearance (e.g., through lane(s), shoulder(s), ramp, C-D road, etc.):

Through lane(s)Shoulder(s)Aux. Lane/Ramp
Existing:____________ m____________ m____________ m
Proposed:____________ m____________ m____________ m

4. Description of work required to achieve the 4.9 m clearance:

Estimated additional cost to obtain 4.9 m clearance: $

5. Reason why 4.9 m vertical clearance cannot be attained:

6. Alternate route with 4.9 m vertical clearance:

7. Anticipated schedule for future project(s) which will correct or improve the substandard clearance:

8. Remarks:

9. Date to MTMCTEA:_____________ Response requested by:______________
    Contact Person:______________ Telephone:______________ Fax:_____________

Updated: 06/27/2017
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000