Publication Details

An examination of the effects of the 55 mph speed limit on North Carolina accidents

Type: book

Author(s): Council, Forrest M.; Pitts, Linda; Sadof, Michael; Dart, Olin K.

Pages: 99

Publisher: UNC Highway Safety Research Center


Publication Date: Apr-1975

Address: Chapel Hill, NC

Abstract: Because of the energy crisis of early 1974 and the resulting measures taken to conserve fuel (e.g., reduction of the maximum speed limit to 55 mph, "self-imposed" gas rationing, etc.), there were dramatic changes in the highway transportation system. This paper examines North Carolina data on vehicle speeds, accident frequency and severity, and traffic counts in an attempt to gain insight into the "causes" of the dramatic reduction in highway fatalities and accidents following these system changes. Emphasis is placed on the effects of the 55 mph speed limit. Comparative analyses of 1973 and 1974 data using various parametric and non-parametric statistical tests indicated major findings, in vehicle speeds, accidents, and traffic counts. These findings, and others, indicate that while any "direct" severity reducing effect of the 55 mph limit may have disappeared, attitude may have continued. Because of this, there is no recommendation that the 55 mph limit be changed on safety groups, but there is a need for continued nonitoring of the system since other contributing factors related to the fuel "crisis" have, in all likelihood, continued to change since late 1974.