FREEWAY CAPACITY AND FLOW RELATIONSHIPS. HIGHWAY CAPACITY AND LEVEL OF SERVICE. PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON HIGHWAY CAPACITY, KARLSRUHE, GERMANY, 24-27 JULY 1991

Currently the Institute of Transportation Studies (ITS) at the University of California is in the process of developing a freeway lane model which will predict flows by lane in the vicinity of ramp junctions and major weaves. To provide information for this model, ITS has studied certain characteristics of straight pipe sections of freeway (away from the influence of ramps) for two, three and four lane sites as described in this paper. These characteristics include lane distribution vs. flow, lane changing vs. flow, and speed vs. flow data for three different sites. One site has a wealth of data points near capacity and the occupancy, mean flow and standard deviation for these data have been determined. Additionally, this research further demonstrates the difference between the value of capacity of a freeway lane cited in the Highway Capacity Manual (HCM) and actual values at these sites, and compares the speed flow curves developed at these sites to the 1985 HCM curve and the JHK curve.