High Density Vehicular Flow-Density Relationships

Experimental research was conducted on vehicular flow-density-speed relationships for conditions ranging from maximum flow to jam density. Investigation was made of the applicability of the Greenshields and Greenberg models for vehicular flow to the experiments which were based on the halting of a high-volume stream of traffic by a traffic signal. Photographic observations provided speeds, densities, and flows for successive pairs of vehicles brought to a halt. After analyzing the material in accordance with the principles of macroscopic car-following, it was concluded that both the Greenshields and Greenberg models provided a good indication of the relationship between speed, density, and flow within the range of densities studied.