Page:America's Highways 1776–1976.djvu/412

 These route and mileage markers aided travelers passing through Jackson, Mich.

Late in 1922, three State highway department officials from Minnesota, Wisconsin, and Indiana joined in a trip through several States to try to work out some basis for uniformity in the signing and marking of their highways. The trio’s findings were reported at the 1923 meeting of the Mississippi Valley Association of State Highway Departments. That body agreed on them as a uniform signing and marking plan for the member States and passed its recommendations on to AASHO. Two years later the system of signs and markers became the basis for the first national standards.

The Mississippi Valley Association established distinctive shapes for the several classes of signs, namely a circular railroad crossing sign, an octagonal stop sign, a diamond-shaped slow sign, and a distinct route marker to be individually designed by each State. All of these signs were to have a white background with black lettering and border. With the exception of the route markers and the rectangular information sign, all were to be two feet square or 2 feet across. Within a year Wisconsin, Minnesota, Indiana, and Michigan were installing signs on their State systems largely in harmony with the Association plan, and other States in the Association were making plans to do so promptly. A Minnesota Highway Department Manual of Markers and Signs was completed in April 1923.

The report of the National Conference on Street and Highway Safety in 1924 by its Committee on Construction and Engineering stated that:

Proper signs and signals are essentia] to the safe movement of traffic on any street or highway. . . . Signs should be uniform for a given purpose throughout the United States. . . . It can be assumed that the Federal-aid signs. . . will lie uniform in every state and will point the way to state and county highway authorities to follow the same standards. . . . All signs should be simple, with the least amount of wording necessary to make them readily understood, depending mainly on distinctive shapes, symbols and colors.

The Conference report recommended that color indications, which would not be used for any other purpose, should be red for “stop”; green for “proceed”; yellow for “caution” at curves; some special cautionary color indications should be used at crossroads; white letters or symbols should be used on the red or green background, and black on the yellow. Distance and direction signs should be black and white.

Other recommendations were :

Railroad crossings remaining at grade should be safeguarded in every reasonable way. Standard warning signs and pavement markings should be used to mark the approaches to all public railroad crossings.

Rural highways should be marked with a white center line on curves, at and near hill crests, at irregular intersections, and at any other points where safety requires that motorists keep strictly to the right. No parking even off the traveled roadway should be permitted opposite these white lines. White center lines should not be used on straight level sections of highway or street except at highway, street or railroad crossings. Black center lines on straight sections of highways are desirable.

Pedestrian lanes should be marked on the pavement at busy intersections.

Objects near the roadway, such as curbs, poles, fences and rock surfaces, should be painted white. Obstructions, such as columns and curbs, at the centers of underpass, should be striped diagonally black and white. 406