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 55mph speed limit.