Changes and revisions to route markings can be the result of new construction, actions of adjoining states or changing conditions in an area. The district must initiate proposed route marking revisions. When considering a route marking change, two items are to be considered:
- Does the recommended marking fit the criteria for the type of route?
- Can the route be signed so it can be easily followed?
The District’s Asset Management Committee, which is comprised of members from each functional unit within the district, will review all changes in route markings. Once the committee has reviewed the change in route marking and all concerns and issues have been addressed, the change in route marking shall be forwarded to Transportation Planning for further processing. The recommendation is to be electronically transmitted and shall include:
- Letter of transmittal, submitted by the district engineer.
- Six color copies of an electronic map with symbols showing the proposed marking.
- Reason for the change.
- Any requests involving Interstates or U.S. numbered routes are to have six AASHTO applications completed.
- Any other supporting information.
|Missouri is the only state to extensively use lettering on its highway system. The 1952 Missouri 10-Year Highway Modernization and Expansion Program (the “Takeover Program”) upgraded 12000 miles of county roads. The roads became known as supplemental routes. The program provided a state-maintained road within 2 miles of 95% of all rural units, such as farm homes, churches, schools, stores, etc. Missouri opted to use letters to label these routes to avoid confusion with the existing numbered routes.|
|"G", "I", "L", "Q", "S" and "X" are not used (with the exception of Route AX near Axtell). "R" (except for Route AR south of Bakersfield) is only used on supplemental routes connecting state parks or other recreational facilities. Usually, but not always, double letter routes are farm to market roads that end at county roads or are former alignments of other highways.|
One to two months should be allowed for a state numbered or lettered route-marking change to be considered and approved. Up to a year is to be allowed for final approval of a proposed change to U.S. or Interstate routes because the AASHTO subcommittee that considers federal route changes only meets twice a year, in the spring and the fall.
The transmittal letter should indicate whether the request involves other states. When a federal route change affects another state, the submittals are to be coordinated and presented to AASHTO at the same meeting.