DIVERSION OF FREEWAY TRAFFIC IN LOS ANGELES: IT WORKED

The California Department of Transportation (Caltrans) implemented a traffic management plan aimed at bringing about voluntary traffic diversion upstream of a section of freeway that needed to be closed for 6 hr for maintenance operations. Without an extensive traffic management effort, delays of more than 2 hr were anticipated. The plan was designed to limit delays on the affected high-volume freeways (160,000 to 225,000 average daily traffic) to a maximum of 20 min. The plan included an aggressive public information campaign before the closure by using both media and freeway signing and an extensive use of changeable message signs during the operation. Significant diversion from two freeways that feed the closure area was achieved. Congestion extended about 2.5 miles upstream of the closure at its maximum; actual delays never exceeded the targeted 20 min. The plan, how it was developed, and how it was implemented are described. Results of the operation are also presented.