University of California Transportation Center

Effective management of travel demand is a growing concern among transportation planners, engineers, local governments and business establishments. Most of the industrialized countries have realized that increasing transport capacity to satisfy travel demand is not a viable option for meeting future needs [AASHTO, 1988]. This realization was the result of growing energy, environmental, and air quality considerations which discouraged the expansion of existing transport systems supply. Transportation consumes 63% of all petroleum used in the United States [EIA, 1988a] and over 70% in California [CEC, 1987]. United States oil imports are forecast to increase from 5.8 million barrels per day in 1987 to between 7.6 and 11.6 million barrels per day by the year 2000 [EIA, 1988b] and the single greatest opportunity for reducing petroleum consumption lies in the transportation sector. On the environmental front, continued reliance on the private automobile continues to raise serious questions about our air quality. In 1987 the Environmental Protection Agency reported that 107 metropolitan areas in the US violated the primary health standard for ozone, carbon monoxide or both [Sperling and Deluchi, 1989]-- 12 of these regions were in California. On-road mobile sources are forecast to to emit 61% of total CO and 47% of NOx (an ozone precursor) in California [CARB, 1988]. Thus, the focus of transportation planning has shifted from the construction of new facilities to the application of efficient travel demand management techniques.