Abstract
This report is another in the continuing study of speeds of vehicles on Indiana highways. Observations of spot speeds were taken on interstate, four-lane and two-lane highways throughout the state during the July-September 1978 quarter. Analysis of the speeds showed the overall average speed for vehicles was 57.2 mph. The overall average speed for passenger cars and all trucks was 57.6 mph and 56.8 mph respectively. These overall average speeds were 0.8 mph less for passenger cars and 0.8 mph less for trucks than speeds found in the April- June 1978 study.