The University of Tennessee, Knoxville


MUTCD History Lesson

by Matt Cate, P.E.

Most of us probably remember several previous editions of the MUTCD. For me, my MUTCD memory begins with the long-obsolete 1988 Edition. The easiest way to look back on the complete history of the MUTCD and its origins is to visit a website maintained by Dr. Gene Hawkins, Associate Professor of Civil Engineering at Texas A&M University (https:// htm). Dr. Hawkins' site includes links to: articles and presentations on the history and evolution of the MUTCD, current MUTCD websites, and complete scanned copies of previous editions of the MUTCD (2003, 2000, 1988, 1978, 1971, 1961, 1948, 1942, and 1935) and its predecessors.

In some ways it is fascinating to see how much the MUTCD has changed over the years. On the other hand, much remains the same. A great example of this evolution can be found in the following excerpts from the original 1935 MUTCD, centering on its discussion of stop signs:

Section 106 - Stop Signs

A STOP sign shall be used only under the following conditions and then only where it is necessary that vehicles come to a stop before proceeding cautiously:

  1. Where restricted view so requires.
  2. Intersection of two main highways.
  3. Intersection of a secondary with a main highway.
  4. End of roadway having no outlet.
  5. Railroad grade crossing where a stop is required by law.
  6. Approach to a drawbridge where a stop is required by law.
  7. Unsignalled intersections in a signalized area.

Stop signs are classified separately from other regulatory signs and are given a distinctive shape, for the reason that violation of them is extremely hazardous. They also have the highest inconvenience factor. Therefore, they should be used only where warning signs would be inadequate. Use at less dangerous points fosters disregard of all STOP signs. Isolated STOP signs, as in a) above, should not be installed unless based on visibility and speed studies.

Whenever a main highway is protected by STOP signs a "through highway" regulation should be in force, and an "ending" sign should be installed at the end of the section so protected.

Section 127 - Materials

Rust-resisting metal should be used for permanent signs and is recommended for all signs, but wood may be used for large signs and also for temporary and seasonal signs, and heavy cardboard may be used for special occasions or emergencies. For all signs the material specifications (see Appendix B) proposed by the Joint Board on Interstate Highways, the U.S. Bureau of Public Roads, the American Association of State Highway Officials, and the National Bureau of Standards should be used.

Non-corrosive bolts, screws and washers should be used for attaching signs to their supports to avoid discoloration.

Section 133 - Illumination

All STOP, slow-type and railroad advance warning signs shall be illuminated at night so as to be visible from all distances up to 350 feet. The outlines and word "STOP" of STOP signs, the outlines of slow-type signs and the outlines and letters "R R" of railroad advance warning signs shall be illuminated.

Less brilliant illumination of the message on slow-type signs is desirable but optional. If a sign is necessary in daylight, it has greater value at night, inasmuch as night driving at high speeds is continually increasing. Illumination of the outline of STOP and slow-type signs will make them visible at ample distance to enable motorists to slow down in time to read and obey the specific message. Illumination of word messages legible a sufficient distance would hardly be feasible. Illumination of the outlines, besides providing advance warning, should have much educational value in impressing upon motorists the significance of shapes.

In any program of replacement of existing equipment the first replacements with standard signs shall be at the most hazardous locations and at places where the signs are not otherwise adequately illuminated.

Section 134 - Method of Illumination

Illumination of signs shall be white, except the lettering on STOP signs, which shall be red. The following methods of illumination are listed in the order of preference:

  1. A light, within or behind the sign, or luminous tubes, illuminating the outline of the sign and the main message, whether symbol or word. The light may be flashing or steady, preferably flashing.
  2. An attached or independently mounted flood light focused on the face of the sign.
  3. Reflecting elements set in the face of the sign.

Flashing or steady lights within the sign, flashing or constantly luminous tubes, or flood lights provide the maximum visibility under all conditions. Because of their higher cost and the difficulty of service connections, however, they will probably not be used very frequently in rural areas.

Reflecting buttons outlining the shape of a sign should be placed on the yellow background just inside of the black border.

The importance of the STOP sign is such that it merits a distinctive color of illumination, and red is so generally recognized as a mark of danger requiring a vehicle to stop that it is the obvious choice for the purpose, especially as its visibility is adequate for permitted speeds.

Street lighting is not generally considered adequate illumination for signs because of inflexible location, reduced light due to foliage, and the fact that street lamps are sometimes not operated during all the hours of darkness.

Section 140 - Detailed Design of STOP Sign

The design and specifications of the standard STOP sign (Fig. 140) shall be as follows:

  1. Shape.-Octagon, with two sides vertical.
  2. Colors.-Yellow background, black or red letters and border; red reflecting buttons for word " STOP," white for border.
  3. Dimensions.-24 by 24 inches, or larger in multiples of 6 inches.
  4. Main Message.-STOP, located in center.
  5. Secondary Message.-Through Traffic, Bad Corner, Road End, Rail Road, or Draw Bridge, located above and below word "STOP."
  6. Letters.-"STOP" in 6-inch letters, Series E; secondary message in 3-inch letters, Series B.

The function of the secondary message is to give the reason for the stop and inform approaching motorists of what to expect.

Section 152 - STOP Signs

STOP signs at highway intersections shall be located at the crosswalk line or, in the absence of a crosswalk, not more than 30 feet from the intersected roadway.

STOP signs at railroad grade crossings shall be located 15 to 50 feet from the nearest track. STOP signs at drawbridges shall be located exactly where it is desired that vehicles stop. STOP signs at street ends shall be located in the center of the roadway at its end.

When possible, a STOP sign should be placed exactly where vehicles are expected to stop. At an intersection it should be as near thereto as possible without encroaching upon the crosswalk, so that operators can have a clear view of traffic approaching from both directions on the main thoroughfare. If, because of rounded curbs, the sign cannot be placed at this point, it should be placed at the end of the curb return and a stop line or marker installed at the stopping point. If curves in the highway reduce visibility, an advance warning sign reading "Stop Sign Ahead" should be used. It is interesting to see that the MUTCD placed significant emphasis on the nighttime visibility of traffic control devices from the very beginning. That certainly places our current efforts to meet minimum retroreflectivity requirements in a new light (I had to say it). It is also interesting to see language warning against the overuse of signs. I'm sure that the members of the 1935 Joint Committee on Uniform Traffic Control Devices would be shocked and awed by the design and application of our modern traffic control devices.


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