The article examines California's progressive approach to the development of `intelligent highways', which uses Automatic Vehicle Identification (AVI) systems for its Intelligent Transportation Systems (ITS). It describes the radio frequency (RF) based system, which is now being installed for three major highway applications in California. In 1992, the California Legislature passed into law Department of Transportation (CalTrans) Title 21, a mandate to regulate electronic toll equipment used in California, which set in motion California's intelligent highway projects, and chose the direction of their technology development. It has influenced the emergence of RF backscatter as the technology of choice in AVI systems for toll roads; backscatter has several advantages. The following significant Californian projects using AVI are described: (1) the SR-91 Express Lanes project, which installed a Texas Instruments TIRIS AVI system on ten miles of toll road near Los Angeles; (2) the Transportation Corridor Agencies' (TCA) Foothill Corridor project near Los Angeles, replacing an existing AVI system with TIRIS; and (3) application of the Advanced Toll Collection and Accounting System (ATCAS) to nine state-owned bridges in California.
Abstract