The installation of these TCD's should be based on the professional judgment of Traffic Engineers after careful study of the location to be controlled. The study should consider such factors as accident frequency and type, vehicle speeds and traffic volumes.
On occasion, an elected official, with a true "politician's" zeal to please everyone, influences the installation of a traffic control device against the advice of the Traffic Engineer. The elected official's motivation is often an angry or persistent citizen rather than the objective professional judgment of the Traffic Engineer.
The March 1990 issue of "Public Roads" magazine, published by the U. S. Department of Transportation, contained an article on "Motorist Compliance With Standard Traffic Control Devices." The article examined the following forms of motorist noncompliance:
The behavioral studies collected compliance and other data at a large number of typical sites over extended periods of time. In the process, hundreds of thousands of motorists were observed. The clear conclusion was that motorist noncompliance does take place.
One of the recommendations in the US DOT article was: "To ensure that the motoring public maintains a healthy respect for TCD's, traffic professionals must use them prudently. Through concerted efforts of the nature outlined above (Engineering, Enforcement and Education), the safety and efficiency of our streets and highways can be maximized."
Another recommendation was to "Apply TCD's consistently to ensure they command respect."