The 2001 National Household Transportation Survey (NHTS) found that the average motor vehicle contains about 1.6 people (see table 16). But a report from the Department of Energy observes that “intercity trips [have] higher-than-average vehicle occupancy rates” (see appendix C-3, page C-3.4).
How much higher? The answer, curiously, comes from the California High-Speed Rail Authority, which commissioned a study that found the average occupancy of autos in intercity trips is 2.4. Any fuel-efficiency comparisons of autos and intercity rail should use this number, not 1.6.
