Letter to the Editor—Fuel Consumption and Right Turn on Red: Comparison between Simple Model Results and Computer Simulation

In a recent presentation, Lieberman and Cohen (Lieberman, E. B., S. L. Cohen. New technique for the evaluation of urban traffic energy consumption and emissions. Presented at the 55th Annual Meeting of the Transportation Research Board, Washington, D.C., January 20, 1976. Transportation Research Record, in press.) calculated the effect on fuel economy and emissions of permitting a right turn on red at signalized intersections. They applied a detailed computer simulation to a network of streets in Washington, D.C. Fuel consumption was obtained by adding up the fuel used to execute each individual maneuver. It is the purpose of this note to point out that, once the change in the average speed in a traffic system has been determined, the change in fuel consumption can be immediately derived using a simple model of the dependence of urban fuel consumption on average traffic speed without the necessity of performing the detailed fuel summation.