GLOSSARY GLOSSARY

Acronyms and Abbreviations

ACRS mpg MVMA AGT AMC NAAQS AQCR BLS NAS NAE Btu NEPA CAFE CBD NHTSA CEQ CID No, CO OCS CPI OPEC CVCC OSHA CVT DOE PIES DOT PL DPI PMT DPM PMVI EGR PRT EPA RSV EPCA SEC ERDA SIE SLT FHWA SMSA FMVSS SRI Sydec FTC TCP GMC TSM GNP UMTA GRT HC U.S.C HE\\’ VMT WAES ICE LARPP WOCA LDV MMBD 365 366 ● Changes in the Future Use and Characteristics of the Automobile Transportation System

Definitions

Adiabatic—Occurring without loss or gain of heat; program and, in many cases, establishes an in automotive engines, a design that incor- upper limit on the amount of funds that can be porates thermal shielding to prevent radiant appropriated for that program.

heat loss-thereby increasing thermal effi- Automated Guideway Transit (AGT)—A class of ciency and allowing recapture of heat from transportation systems in which unmanned the exhaust stream. vehicles are operated on fixed guideways Air Cushion Restraint System (ACRS)—An auto- along an exclusive right-of-way. Commonly, motive safety device in which a sensor, ac- AGT systems are divided into three classes: tivated by the rapid deceleration caused by Shuttle-Loop Transit, Group Rapid Transit, impact with another vehicle or a fixed object, Personal Rapid Transit. triggers a mechanism that inflates air bags in Automobile—As used in this study, a four-wheeled front of the driver and front-seat passengers. vehicle, with a gross weight of less than 6,000 The driver bag is housed in the steering wheel pounds, designed primarily for use as a pas- hub. The passenger bag is in the area typically senger . Coupes, sedans, and station used for a glove compartment. wagons of all sizes are considered automo- Air Quality Control Region (AQCR)—A geographic biles. Light-duty and vans, even area, designated by the Federal Government, though used as passenger vehicles, are not where two or more communities either in the classed as automobiles. Motorcycles and same or different States have the same air mopeds are also excluded. quality or share a common air pollution prob- Barrel—A measure of petroleum or petroleum prod- lem. ACQRS were established by the Clean ucts, equivalent to 42 U.S. gallons. Air Act of 1963 as the areas in which attain- Brayton Cycle Engine—A high-speed, external com- ment of National Ambient Air Quality Stand- bustion engine in which expanding gases from ards is to be measured. Currently there are continuously burning fuel are used to drive a 247 such regions in the United States and its turbine. Most of the turbine output is used as territories. motive power, but some is used to drive a Air Quality Standards—The prescribed level of pol- compressor to provide air for the combustion lutants in the outside air that cannot be ex- process. (Also known as Gas Turbine Engine. ) ceeded legally during a specified time in a British Thermal Unit (Btu)—The quantity of heat re- specified geographic area. (Also called Na- quired to raise the temperature of 1 pound of tional Ambient Air Quality Standards. ) water 1 degree Fahrenheit at or near 39.2 F. Allocation—An administrative distribution of funds (used as a measure of the energy content of by the Federal Government among the States fuels). (performed for funds that do not have legis- Corporate Average Fuel Economy (CAFE)–The latively mandated distribution formulas). sales-weighted average fuel consumption (in Appropriation—A legislative action that makes mpg) for all passenger vehicles sold by an funds available for expenditure with specific automotive manufacturer in a given model limitations as to amount, purpose, and dura- year. tion. In most cases, an appropriation act per- Capacity (Highway)—The maximum number of ve- mits money previously authorized by substan- hicles that can pass over a given section of a tive legislation to be obligated and payments lane or roadway in one direction (or in both to be made. In the highway program, appro- directions for a two-lane or three-lane high- priations specify the amount of funds which way) during a given time period under pre- Congress make available to liquidate vailing roadway and traffic conditions. prior obligations; that is, the sum of all pay- Categorical Grant—As applied to highway financ- ments of vouchers to be submitted during a ing, funding from a higher level of govern- given fiscal year. Highway appropriations ment (Federal or State) that is earmarked for permit the payment of obligations incurred in expenditure for particular purposes. previous years. Central Business District (CBD)—Usually the down-

Arterial—A highway primarily for through traffic, town retail trade area of a city, or generally an usually a continuous route. area of very high land valuation, traffic flow, Authorization—Substantive legislation that em- and concentration of retail business offices, powers an agency to implement a particular theaters, hotels, and service businesses. Glossary ● 367

Diesel

Diesel

Crash 368 ● Changes in the Future Use and Characteristics of the Automobile Transportation System

3. Interstate System-Technically The Na- Hydrocarbon Fuels—Fuels that contain an organic tional System of Interstate and Defense chemical compound of hydrogen and carbon. Highways; a system of freeways estab- Intermediate-Size Car—A pre-1975 automobile in- lished by the Federal Government in 1944 dustry designation for with a to connect principal cities and industrial between 112 and 118 inches. (See Vehicle Size areas. Class. ) 4. Federal-Aid Urban System/-A system of Internal Combusiton Engine (ICE)—Any engine, roads, including some extensions of the In- either reciprocating or rotary, in which the terstate System, that serves major urban fuel is burned inside of the engine. activity centers and includes high-volume Interstate Highway System—(See National System of arterial and collector routes and access Interstate and Defense Highways. ) roads to terminals of other transportation Jitney–A car or small bus that carries passengers modes. over a regular route according to a flexible Fleet—The total stock of vehicles in use in the coun- schedule. try. Lead —Tetraethyl lead or any other organo-metallic Freeway (Expressway)—A divided arterial highway lead compound added to gasoline to prevent designed for the safe unimpeded movement of engine knock. large volumes of traffic, with full control of Light-Duty Vehicle (LDV)—Any either access and grade separations at intersections. designed primarily for transportation of Fuel Cell—An electrical power source in which fuel goods and rated at 6,000 pounds gross vehicle and oxidant are fed continuously to the elec- weight (GVW) or less, or designed primarily trodes, converting chemical energy into elec- for transportation of persons and having a 12 trical energy directly, without the need to capacity of persons or less. recharge an electrical outlet. Light —A truck with a gross vehicle weight of 10,000 pounds or less. Gross National Product (GNP)—The market value Local Street—A street intended only to provide ac- of all goods and services produced by the Na- cess to abutting properties. tion’s economy. As calculated quarterly by Mass Transit—For-hire, common-carrier, ground the Department of Commerce, gross national passenger transportation service provided for product is the broadest available measure of travel within communities or metropolitan the level of economic activity. areas. Included are all forms of surface, ele- Gross Vehicle Weight—The weight of the empty vated and subsurface modes that use fixed vehicle plus the weight of the maximum an- guideways or operate on streets, highways or ticipated load. (See also Curb Weight. ) waterways. All air transportation modes are Highway Trust Fund—A trust fund established by excluded. Congress in 1956 to finance construction of Methanol—A light, volatile, poisonous liquid alco-

the 45,000-mile National System of Interstate hol (CH40) formed in the destructive distilla- and Defense Highways. Trust Fund revenues tion of wood or made synthetically. accrue from highway user taxes. Middle Distillates—A category of petroleum fuel that Household—All persons occupying a housing unit. includes home heating oil and the diesel fuels Household Formation—The establishment of new burned by surface transportation carriers. households (individuals, couples, or families); Mobility—The satisfaction of travel demand. The the consumer unit that rents or buys and oc- parameters of mobility are number of trips, cupies housing units. New households are trip length, number of persons served, and the formed by marriage, divorce or separation, mode of transportation. children moving from their parents’ homes to Modal Split—The distribution of person trips by their own dwelling units, or movement from mode of travel. group quarters to individual dwelling units. Motor Bus—A rubber-tired, self-propelled, manually Hybrid Vehicle—A vehicle with two propulsion sys- steered transit vehicle with fuel supply carried tems that use different sources of energy— on board. typically an energy storage system (battery or National Ambient Air Quality Standards flywheel) and an internal-combustion engine (NAAQS)—The prescribed levels of atmos- to provide auxiliary power for periods of pheric pollutants that cannot be exceeded heavy load, such as during acceleration or legally during a specified time in a specified high-speed cruise. geographic area. NAAQSS are established by Hydrocarbon—An organic compound made up en- EPA under the authority of the Clean Air Act tirely of carbon and hydrogen. of 1970. Glossary ● 369 370 ● Changes in the Future Use and Characteristics of the Automobile Transportation System

helium or hydrogen) that drives a piston. The derives its name from the fact that it acts on expanded (and thus cooled) working fluid is the three major atmospheric pollutants in au- compressed and reheated for another piston tomobile exhaust. stroke. Transit—(See Mass Transit. ) Stratified-Charge Engine—A slightly modified Otto Truck—A motor vehicle designed primarily for cycle engine in which fuel is fed into the goods movement which is used on public cylinders in a way that produces a rich fuel-air highways and streets. mixture near the spark plug and a lean mix- Turbocharger—An air compressor driven by exhaust ture elsewhere. The spark plug ignites the rich gases from an engine and used to force the mixture which, in turn, ignites the lean mix- fuel-air mixture into the cylinders at greater ture, producing a more complete burn and in than atmospheric pressure, thereby boosting some designs, a more efficient use of fuel. the power of the engine. —A pre-1975 automobile industry Vehicle Damage Protection—Vehicle design features designation for cars with a wheelbase of 100 intended to reduce the cost of damage to the inches or less. After 1975 these cars are in- vehicle in low-speed collisions. These features cluded in the small category. (See Vehicle Size have no effect on death or injury to vehicle oc- Class. ) cupants. (See also Crashworthiness. ) Synthetic Fuel (Synfuel)—A fuel that does not exist Vehicle Miles Traveled (VMT)—One vehicle travel- in nature, but can be manufactured or synthe- ing one mile. As an aggregate measure, VMT sized from natural materials. Generally, syn- represents the travel by all vehicles on a given thetic fuels are derived from other forms of roadway or on all roadways in a specified fossil fuels that are less convenient for con- geographic area during a given time period. sumer use. Synthetic liquid fuels are produced Vehicle Size Class—A classification of motor vehicles from coal, shale, and tar sands. by length. Pre-1975 and post-1975 size classes Tar sands—Geological deposits of sand and clay that are shown in the following table: are heavily impregnated with oil. Pre-1975 Post-1975 Three-Way Catalyst—A treatment system for auto- Subcompact (100” or less) Small (less than 100” ) mobile exhaust that employs platinum or Compact ( 101” -111“) Medium (100” - 112”) rhodium as the active noble metal catalyst for Intermediate ( 112” - 118”) Large (over 112”)

conversion of HC, CO, and NOX. The device Standard (119” or over)