A study performed by Davis and Fitzpatrick of Minnesota Mining and Manufacturing Company, in conjunction with the Minnesota Highway Department in 1952-1953, measured changes in reflectivity of highway sign materials due to "spray" and "splash" on a two-lane, rural highway with turf shoulders. The report, entitled "Sign Placement to Reduce Dirt Accumulation" is presented in HRB Bulletin 89, "Night Visibility", 1954.
The purpose of this study was very similar - to investigate the pattern of spray from passing vehicles with respect to determining the optimum lateral and vertical placement of milepost markers for an Interstate-type highway with wider, paved shoulders.
This paper will describe a 1963 study designed to evaluate further the use of color systems in guiding traffic through highway interchanges. The study was an outgrowth of a similar study conducted in 1959 which suggested that reflectorized color systems could be considered effective in reducing driver problems related to nighttime visibility conditions.
As with the 1959 study, traffic stream characteristics were measured before and after the color treatment was installed, and roadside interviews were conducted to obtain driver's reactions to the treatment.
