NOTES: Light trucks include sport utility vehicles, minivans, and pickup trucks. See Glossary for definitions of transit rail service types. To make it easier to compare data of differing magnitudes over time on the figures, the Bureau of Transportation Statistics divided the data for all years in each category (see table 1-21b in appendix B) by the initial year value.
SOURCE: 1993–1994: U.S. Department of Transportation (USDOT), Federal Highway Administration (FHWA), Highway Statistics Summary to 1995 (Washington, DC: 1997), table VM-201A. 1995–2003: USDOT, FHWA, Highway Statistics (Washington, DC: Annual issues), table VM-1.