Regional variation among selected factors affecting energy use in highway transportation is described and analyzed. Highway vehicle use accounts for about 95% of all motor gasoline used and a substantial portion of the diesel fuel consumed in the US. For the purposes of analysis, highway energy use can be divided into three sectoral users: household, commercial, and government. Chapter 1, Nonhighway Use of Gasoline, covers agriculture, marine, aviation, industrial and commercial, construction, snowmobiles, and motorcycles. Chapter 2, Topics in Commercial Highway Energy Use, includes the following: Commercial Use of Gasoline in Highway Transportation, Automotive Fleets and Electric Vehicle Applicability; Local and Short-Haul Commercial Trucking; Intercity Trucking; and Intracity Bus Service. Chapter 3, Selected Characteristics of Highway Energy Use by the Household Sector, includes sections entitled: Regional Gasoline Use; Ownership of New and Used Vehicles; Fuel Efficiencies and Market Shares of New Vehicle Registrations; Regional Trends in Import Passenger Car Sales and in Light Truck and Van Sales; Regional Variations in Recreational Vehicle Shipments and in Gasoline Consumption, 1977; Regional Patterns of Motorcycle and Moped Use; and An Analysis of the Differences in Carpooling Across Metropolitan Areas. (ERA citation 05:022584)