| Terms | Definitions |
|---|
| N/A | Not applicable. ( Fatality Analysis Reporting System ) |
| NAAQS | National Ambient Air Quality Standards. Maximum permitted quantities of certain pollutants in air, as per the regulations of the United States Environmental Protection Agency. ( Highway Perfomance Monitoring System ) |
| NH3 Emissions | Ammonia emissions, one of the six criteria air pollutants that EPA has set national air quality standards for. ( National Emissions Trends ) |
| NOx Emissions | Nitrogen Oxide emissions, one of the six criteria air pollutants that EPA has set national air quality standards for. NOx is the generic term for a group of highly reactive gases, all of which contain nitrogen and oxygen in varying amounts. Many of the nitrogen oxides are colorless and odorless. Nitrogen oxides form when fuel is burned at high temperatures, as in a combustion process. The primary sources of NOx are motor vehicles, electric utilities, and other industrial, commercial, and residential sources that burn fuels. ( National Emissions Trends ) |
| NRC | The National Response Center (NRC), a division of the U.S. Coast Guard, is the sole federal point of contact for reporting oil and chemical spills. ( Pipeline Safety Statistics, Marine Casualty and Pollution Database ) |
| National Highway System | The National Highway System is a network of nationally significant highways approved by Congress in the National Highway System Designation Act of 1995. It includes the Interstate System and nearly 114,000 miles of arterial and other roads and connectors to major intermodal terminals. ( Highway Perfomance Monitoring System ) |
| The system of highways designated and approved in accordance with the provisions of 23 U.S.C. 103b. The National Highway System consists of the Interstate System, some rural and urban principal arterial routes, and other roads that are important to the national strategic defense system. ( Fatality Analysis Reporting System, General Estimates System (NASS/GES) ) |
| This system of highways designated and approved in accordance with the provisions of 23 U.S.C. 103b. ( Trucks Involved Fatal Accidents ) |
| National Park System | The National Park Service, a bureau of the U.S. Dept. of the Interior, was established in 1916 to oversee the administration of 40 national parks and monuments under the charge of the department. The National Park System now comprises some 380 areas of scenic, historic, or scientific interest totaling more than 84 million acres (34 million hectares). The units are classified into natural, historical, recreational, and cultural groupings to facilitate park management and to identify areas by their prominent characteristics. ( National Ferry Database ) |
| Nautical Mile | An international unit equal to 6076.115 feet. ( National Ferry Database ) |
| Net Registered Tonnage | See Net Tonnage. ( Foreign Traffic Vessel Entrances and Clearances ) |
| Net Tonnage | The remainder after deducting from the gross tonnage of the vessel the tonnage of crew spaces, master's accommodations, navigation spaces, allowance for propelling power, etc. It is equal to (0.2+0.02 log10(Vc)) Vc (4d/3D)2. For passenger ships the following formula is added: 1.25 (GT+10000)/10000 (N1+(N2/10)). Vc is the volume of cargo holds, D is the distance between ship's bottom and the uppermost deck, d is the draught N1 is the number of cabin passengers, and N2 is the number of deck passengers. It is expressed in tons of 100 cubic feet. ( Foreign Traffic Vessel Entrances and Clearances ) |
| New England Division | Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut ( American Travel Survey ) |
| Night | From 6 p.m. to 5:59 a.m. ( Fatality Analysis Reporting System ) |
| Nights Away From Home | The number of nights spent away from home on one trip, including nights spent at the destination, on stops to and from the destination and on side trips away from the destination. Nights away from home are broken into categories including nights at the destination, nights at stops and side trips, and nights en route. ( American Travel Survey ) |
| Non-Motorist | A pedestrian, cyclist, occupant of a vehicle not in transport, person riding a horse, occupant of an animal-drawn conveyance, person associated with a non-motorist conveyance (e.g., baby carriage, skateboard, wheelchair), or other non-motorist (e.g., person outside a trafficway, person in a house). ( General Estimates System (NASS/GES) ) |
| Non-Revenue Traffic | Passengers and cargo transported by air for which no renumeration or token service charges are received by the air carrier. Airline employees, officers and directors, or other persons, except for ministers of religon, who are traveling under reduced rate transportation authorized by 49 U.S.C. 41511(a) and 14CFR part 223, as well as travel agents, cargo agents, and tour conductors traveling at reduced fares are also considered nonrevenue traffic. ( Air Carrier Summary Data ) |
| Non-Scheduled Service | Revenue flights, such as charter flights, that are not operated in regular scheduled service. ( Small Air Carrier Statistics, Air Carrier Financial Reports (Form 41 Financial Data) ) |
| Non-motorist | Any person who is not an occupant of a motor vehicle in transport and includes the following: 1. Pedestrians 2. Pedalcyclists 3. Occupants of parked motor vehicles 4. Others such as joggers, skateboard riders, people riding on animals, and persons riding in animal-drawn conveyances. ( Fatality Analysis Reporting System ) |
| Non-motorist Location | The location of non-motorists at time of impact. Intersection locations are coded only if non-motorists were struck in the area formed by a junction of two or more trafficways. Non-intersection location may include non-motorists struck on a junction of a driveway/alley access and a named trafficway. Non-motorists who are occupants of motor vehicles not in transport are coded with respect to the location of the vehicle. ( Fatality Analysis Reporting System ) |
| Nonattainment Area | Areas of the country where air pollution levels persistently exceed the national ambient air quality standards. ( Highway Perfomance Monitoring System ) |
| Noncollision | A class of crash in which the first harmful event does not involve a collision with a fixed object, nonfixed object, or a motor vehicle. This includes overturn, fire/explosion, falls from a vehicle, and injuries in a vehicle. ( Fatality Analysis Reporting System ) |
| Nonmotorist | Any person who is not an occupant of a motor vehicle in transport and includes the following: 1. Pedestrians 2. Pedalcyclists 3. Occupants of parked motor vehicles 4. Others such as joggers, skateboard riders, people riding on animals, and persons riding in animal-drawn conveyances. ( Fatality Analysis Reporting System ) |
| Nonmotorist Location | The location of non-motorists at time of impact. Intersection locations are coded only if non-motorists were struck in the area formed by a junction of two or more trafficways. Non-intersection location may include non-motorists struck on a junction of a driveway/alley access and a named trafficway. Non-motorists who are occupants of motor vehicles not in transport are coded with respect to the location of the vehicle. ( Fatality Analysis Reporting System ) |
| Nonoperating Income And Expense | Interest income and expense, unusual foreign exchange gains or losses, and capital gains or losses in disposition of property and equipment. ( Air Carrier Financial Reports (Form 41 Financial Data) ) |
| Number Exceed | The number of times the pollution concentration values exceeded the air quality standard for a criteria air pollutant during one year. For example, in the case of a 3-hour standard, the number of 3-hour values that were greater than the 3-hour standard during one year. Some pollutants have multiple air quality standards. See also Exceedence. ( National Air Quality Data (AIRS) ) |
| Number Of Passenger Cars In Operation | The maximum number of passenger cars actually operated to provide service on an average weekday, average Saturday and average Sunday. ( National Transit Database ) |
| Number Of Trains In Operation | The maximum number of trains actually operated to provide service on an average weekday, average Saturday and average Sunday. ( National Transit Database ) |
| Number Of Vehicles In Operation | The maximum number of vehicles actually operated to provide service on an average weekday, average Saturday and average Sunday. ( National Transit Database ) |
| Number of Observations | Number of 1-hour values (observations) reported for the year. Uninterrupted monitoring would produce 8760 values per year (24 hours * 365 days). ( National Air Quality Data (AIRS) ) |
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