Caltrans manages more than 50,000 miles of California's highway and freeway lanes, provides inter-city rail services, permits more than 400 public-use airports and special-use hospital heliports, and works with local agencies. Caltrans carries out its mission of improving mobility across California with six primary programs: Aeronautics, Highway Transportation, Mass Transportation, Transportation Planning, Administration and the Equipment Service Center.

In recognition that California could not merely build its way out of traffic congestion and air pollution, Caltrans began to emphasize the more-efficient use of highways and their integration with other "modes" of transportation. Public sentiment became more receptive to rail and transit, car pooling, ramp metering, telecommuting flexible work hours, and research into intelligent vehicle and highway systems.