|Number registered (thousands)||3,681||4,232||4,374||4,593||4,487||4,481||4,370||4,408||4,906||5,024||5,266||5,293||5,735||5,763||5,926||5,704||5,651||5,667|
|Vehicle-miles (millions)||27,100||34,600||39,800||45,400||51,900||52,900||53,900||56,800||61,300||62,705||64,072||66,893||68,021||70,304||70,500||72,448||(R) 75,866||77,562|
|Fuel consumed (million gallons)||3,968||5,420||6,923||7,399||8,357||8,172||8,237||8,488||9,032||9,216||9,409||9,576||6,817||9,372||9,563||9,667||(R) 10,321||10,690|
|Average miles traveled per vehicle (thousands)||7.4||8.2||9.1||9.9||11.6||11.8||12.3||12.9||12.5||12.5||12.2||12.6||11.9||12.2||11.9||12.7||13.4||13.7|
|Average miles traveled per gallon||6.8||6.4||5.7||6.1||6.2||6.5||6.5||6.7||6.8||6.8||6.8||7.0||10.0||7.5||7.4||7.5||7.4||7.3|
|Average fuel consumed per vehicle (gallons)||1,078||1,281||1,583||1,611||1,862||1,824||1,885||1,926||1,841||1,835||1,787||1,809||1,189||1,626||1,614||1,695||(R) 1,826||(R) 1,886|
KEY: R = revised.
a Beginning in 1998, the Federal Highway Administration (FHWA) used the Census Bureau's 1997 Vehicle Inventory and Use Survey (VIUS) for its baseline estimate of single-unit 2-axle 6-tire or more trucks. Prior to 1998, the FHWA used the Census Bureau's 1992 Transportation Inventory and Use Survey (TIUS) for its baseline estimates. Therefore, post-1997 data may not be comparable to 1997 and earlier years.
In 1995, the U.S. Department of Transportation, Federal Highway Administration revised its vehicle categories beginning with 1993 data to include passenger cars, other 2-axle 4-tire vehicles, single-unit 2-axle 6-tire or more trucks, and combination trucks. Single-unit 2-axle 6-tire or more trucks are on a single frame with at least 2 axles and 6 tires. Pre-1993 data have been reassigned to the most appropriate category.
1970-94: U.S. Department of Transportation, Federal Highway Administration, Highway Statistics Summary to 1995, FHWA-PL-97-009 (Washington, DC: July 1997), table VM-201A.
1995-2003: Ibid., Highway Statistics (Washington, DC: Annual issues), table VM-1.