| Terms | Definitions |
|---|
| MARPOL | The International Convention for the Prevention of Pollution from Ships. The MARPOL Convention is the main international convention covering prevention of pollution of the marine environment by ships from operational or accidental causes. It is a combination of two treaties adopted in 1973 and 1978 respectively and updated by amendments through the years. ( Marine Casualty and Pollution Database ) |
| The international treaty regulating disposal of wastes generated by normal operation of vessels. ( Marine Casualty and Pollution Database ) |
| MC | Marine Casualty case. ( Marine Casualty and Pollution Database ) |
| MCS-150 | MCS-150 is a truck identification form collected by the Federal Motor Carrier Safety Administration. ( Trucks Involved Fatal Accidents ) |
| MSIS | Marine Safety Information System database. ( Marine Casualty and Pollution Database, National Ferry Database ) |
| Maintenance Expense | All expenses, both direct and indirect, specifically identifiable with the repair and upkeep of property and equipment. ( Air Carrier Financial Reports (Form 41 Financial Data) ) |
| Manner of Collision | A classification for crashes in which the first harmful event was a collision between two motor vehicles in transport. ( Fatality Analysis Reporting System ) |
| Marine Violation Case | A vessel or other waterway incident deemed an alleged violation of US Coast Guard safety and environmental regulations (e.g., an oil spill). The incident will be examined by a USCG hearing officer, and a penalty may be imposed for the alleged violation. ( Marine Casualty and Pollution Database ) |
| Market | A market is defined by the first departure airport on a ticket and the ultimate arrival airport. The market origin and destination airports differ from segment origin and destination airports in that there may be intermediate destinations and more than one plane may be used. ( Airline Origin and Destination Survey (DB1B) ) |
| Marketing Carrier | An air carrier that issued a flight reservation or ticket under a codeshare agreement. ( Airline Origin and Destination Survey (DB1B) ) |
| Maximum Operating Pressure | Maximum pressure permitted for normal pipeline operations, which is related to pipe's strength and ability to withstand internal pressure. ( Pipeline Safety Statistics ) |
| Means of Transportation | A mode used for going from one place (origin) to another (destination). Includes private and public modes, as well as walking. For all travel day trips, each change of mode constitutes a separate trip. ( Nationwide Personal Transportation Survey ) |
| A mode used for going from one place (origin) to another (destination). Includes private and public modes, as well as walking. For all travel day trips, each change of mode constitutes a separate trip. The following transportation modes, grouped by major mode, are included: ( Nationwide Personal Transportation Survey ) |
| Metal Fatigue | Weakened condition induced in metal parts of machines, vehicles, or structures by repeated stresses or loadings. ( Hazardous Material Incident Reporting System (HMIRS) ) |
| Metar Weather Report | Meteorological Terminal Aviation Routine Weather Report. ( Aviation Accidents Database and Synopses ) |
| Metered Ramp | An access ramp leading to a major road (e.g., a highway) with a traffic signal that is used to regulate the rate at which vehicles enter the road. Metered ramps may be used to reduce congestion on major roads or to balance the speed of traffic on parallel roads so that traffic is more evenly distributed. ( Highway Perfomance Monitoring System ) |
| Methanol | A light, volatile alcohol (CH3OH) eligible for motor gasoline blending. ( National Transit Database ) |
| Metric Tons | 2,204.6 pounds or 1,000 kilograms. ( Foreign Traffic Vessel Entrances and Clearances ) |
| Metropolitan Area | A large population nucleus, together with adjacent communities that have a high degree of economic and social integration with that nucleus. A metropolitan area (MA) may be defined around two or more nuclei. The MA is a statistical standard designated and defined by the Office of Management and Budget, following a set of official published standards. An MA comprises one or more counties except in New England where MAs are composed of cities and towns rather than whole counties. Classifications of MAs include metropolitan statistical area (MSA) and consolidated metropolitan statistical area (CMSA) that is divided into primary metropolitan statistical areas (PMSA). ( American Travel Survey ) |
| Metropolitan Statistical Area | A relatively freestanding metropolitan area (MA) that is not closely associated with other MAs. These areas typically are surrounded by nonmetropolitan counties. A metropolitan statistical area (MSA) comprises one or more counties except in New England where MSAs are composed of cities and towns rather than whole counties. ( American Travel Survey ) |
| An MSA is a county or group of contiguous counties that contains at least one city with a population of 50,000 or more or a Census Bureau-defined urbanized area of at least 50,000 with a metropolitan population of at least 100,000. In addition to the county or counties that contain all or part of the main city or urbanized area, an MSA may contain other counties that are metropolitan in character and are economically and socially integrated with the main city. ( National Ferry Database, Census Transportation Planning Package ) |
| Metropolitan Statistical Area (MSA) | An MSA is a county or group of contiguous counties that contains at least one city with a population of 50,000 or more or a Census Bureau-defined urbanized area of at least 50,000 with a metropolitan population of at least 100,000. In addition to the county or counties that contain all or part of the main city or urbanized area, an MSA may contain other counties that are metropolitan in character and are economically and socially integrated with the main city. ( State and Area Employment, Hours, and Earnings, Nationwide Personal Transportation Survey, Occupational Employment and Wage Estimates ) |
| Mid Atlantic Division | New York, New Jersey, Pennsylvania ( American Travel Survey ) |
| Midday | The period between the end of the AM peak and the beginning of the PM peak. ( National Transit Database ) |
| Midgrade | Gasoline having an antiknock index, i.e., octane rating, greater than or equal to 88 and less than or equal to 90. Note: Octane requirements may vary by altitude. ( U.S. Retail Gasoline Prices ) |
| Mile | A statute mile (5,280 feet). All mileage computations are based on statute miles. ( Air Carrier Statistics ) |
| Minor Arterial | Streets and highways linking cities and larger towns in rural areas in distributing trips to small geographic areas in urban areas (not penetrating identifiable neighborhoods). ( Vehicle Miles Traveled ) |
| Minor Arterials | Streets and highways linking cities and larger towns in rural areas in distributing trips to small geographic areas in urban areas (not penetrating identifiable neighborhoods). ( Fatality Analysis Reporting System ) |
| Mode Of Transportation | The type of transportation used for moving a shipment to its domestic destination. For exports, the domestic destination is the port of exit. ( Commodity Flow Survey ) |
| Monitor Type | A code identifying the administrative classification of the monitor. This data is included for each pollutant. Values are: NAMS (National Air Monitoring Stations), SLAMS (State and Local Air Monitoring Stations), PAMS (Photochemical Assessment Monitoring Stations), PAMS/Unofficial (site certification pending), PAMS/NAMS (part of both NAMS and PAMS monitoring networks), PAMS/SLAMS (part of both SLAMS and PAMS monitoring networks), Index, Industrial, Tribal, Non-EPA Federal (operated by a Federal agency other than EPA), Other, Unknown and Not Available (no value provided). ( National Air Quality Data (AIRS) ) |
| Monohull | A vessel with a single hull. ( National Ferry Database ) |
| Monorail | A transit mode that is an electric railway of guided transit vehicles operating singly or in multi-car trains. The vehicles are suspended from or straddle a guideway formed by a single beam, rail or tube. ( National Transit Database ) |
| Most Harmful Event | The event during a crash for a particular vehicle that is judged to have produced the greatest personal injury or property damage. ( Fatality Analysis Reporting System ) |
| Motor Carrier Classification A | The operation classification for authorized for-hire trucks. Trucks in this classification provide transportation for compensation as a common or contract carrier of property, owned by others, or passengers under the provisions of the FMCSA. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification B | The operation classification for exempt for-hire trucks. These trucks provide transportation for compensation of property or passengers exempt from the economic regulations of FMCSA. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification C | The operation classification for private property trucks. These trucks provide transportation of property by commercial motor vehicle and are not for-hire motor carriers. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification D | The operation classification for business-owned private passenger trucks. This classification includes private motor carriers engaged in the interstate transportation of passenhers which is provided in the furtherance of a commercial enterprise and is not available to the public at large (e.g., bands). ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification E | The operation classification for non-business-owned private passenger trucks. This classification includes private motor carriers involved in the interstate transportation of passengers that does not otherwise meet the definition of a private motor carrier of passengers (e.g., church buses). ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification F | The operation classification for migrant trucks. This classification includes interstate transportation, including a contract carrier, but not a common carrier of 3 or more migrant workers to or from their empoyment by any motor vehicle other than a passenger automobile or station wagon. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification G | The operation classification for U.S. Mail trucks. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification H | The operation classification for U.S. Federal Government trucks. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification I | The operation classification for state government trucks. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification J | The operation classification for local government trucks. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification K | The operation classification for Indian tribe trucks. This classification includes trucks used to transport property or passengers by an Indian tribal government. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Carrier Classification L | The operation classification for other trucks not described by Motor Carrier Classifications A through K. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Motor Vehicle in Transport | A motor vehicle in motion on the trafficway or any other motor vehicle on the roadway, including stalled, disabled, or abandoned vehicles. ( Fatality Analysis Reporting System ) |
| Motorcycle | A two- or three-wheeled motor vehicle designed to transport one or two people, including motorscooters, minibikes, and mopeds. ( Fatality Analysis Reporting System ) |
| Motorized Vehicle | Includes all vehicles that are licensed for highway driving. Specifically excluded are snow mobiles, minibikes, etc. ( Nationwide Personal Transportation Survey ) |
| Mountain Division | Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada ( American Travel Survey ) |
| Multiple Modes | Parcel, U.S. Postal Service or courier shipments or shipments for which two or more of the following modes of transportation were used: private truck, for-hire truck, rail, shallow draft vessel, deep draft vessel, or pipeline. ( Commodity Flow Survey ) |
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