Book Description

This report summarizes results of a study of detector placement on the diamond interchange frontage road (ramp) using the Texas Intersection Simulation Model. The criterion used for the optimization is the minimization of delay. A secondary criterion is to reduce the dilemma zone to a minimum. The results indicate that the first detector located along the frontage road (ramp) should be placed about 30 meters (100 feet) back from the stop bar. The remainder of the layout should provide a vehicle interval between 1.1 and 1.3 seconds and not trap a vehicle a the design speed in a dilemma situation. The recommended layout of detectors achieves these two goals.