This report presents analytic procedures and guidelines for the comparative evaluation of the three modes of freeway entrance ramp control: pretimed, local actuated, and system. These procedures are applicable in determining whether or not entrance ramp control can be employed beneficially and, if so, the type of control mode that is most appropriate. Incremental travel-time benefits, fuel-consumption benefits, and vehicle emissions benefits are expressed relative to the pretimed control mode. The benefit and performance data necessary to permit comparative analysis and design were obtained by analyzing operational data from existing systems and through simulation studies. The results of a questionnaire were used to formulate a baseline freeway definition. The effect of mode sensitive properties, such as fluctuating demand, were determined by simulation of the baseline freeway. Although the simulation results are reasonable, they have not been calibrated or verified by field measurement. The FREFLO traffic simulation model was developed by modifying the existing MACK model. Detailed costs of ramp control installations were also obtained.
Abstract