Urban Arterial Speed-Flow Equations for Travel Demand Models

This paper describes the effort to improve the speed-flow relationships for urban arterial streets that are contained in the Southern California Association of Governments metropolitan area travel demand model.  Intersection traffic counts and floating car runs were made over 4-hour long periods on one-mile long sections of 8 different arterial streets within the City of Los Angeles.  Of the speed-flow equations tested, the Akcelik equation performed the best for over-capacity situations and performed as well as other possible equations for under-capacity conditions.