| Terms | Definitions |
|---|
| DRM | Directional Route Miles; The mileage in each direction over which public transportation vehicles travel while in revenue service. It is computed with regard to direction but without regard to the number of traffic lanes or rail tracks existing in the row. ( National Transit Database ) |
| DUI | Driving Under the Influence; The driving or operating of any vehicle or common carrier while drunk or under the influence of liquor or narcotics. ( National Transit Database ) |
| DWI | Driving While Intoxicated ( Trucks Involved Fatal Accidents ) |
| Driving while intoxicated, or driving while impaired. General term used to describe the criminal action of operating a vehicle while intoxicated, impaired or under the influence of alcohol or other drugs. ( Fatality Analysis Reporting System ) |
| Damaged Stability | The international maritime standard requiring passenger ships to subdivide the ship into watertight compartments such that after assumed damage to the ship's hull the vessel will remain afloat and stable. This standard is defined in Chapter II of SOLAS, the international convention for the Safety of Life at Sea. ( Marine Casualty and Pollution Database ) |
| Day | From 6 a.m. to 5:59 p.m. ( Fatality Analysis Reporting System ) |
| Deadweight Tonnage | The lifting capacity of a ship expressed in long tons (2,240 lbs.), including cargo, commodities, and crew. ( Marine Casualty and Pollution Database ) |
| Dedicated Taxes | Any taxes raised specifically for transit purposes and which are dedicated at their source, rather than through an appropriation of general funds. ( National Transit Database ) |
| Deep Draft Vessel | A barge, ship, or ferry operating primarily in the open ocean. (Shipping on the Great Lakes and St. Lawrence Seaway is classified with shallow draft vessels.) ( Commodity Flow Survey ) |
| Demand Response | A transit mode comprised of passenger cars, vans, or class C buses operating in response to calls from passengers or their agents to the transit operator, who then dispatches a vehicle to pick up the passengers and transport them to their destinations. The vehicles do not operate over a fixed route or on fixed schedules. ( National Transit Database ) |
| Departure Delay | The difference between the scheduled departure time and the actual departure time from the origin airport gate. ( Airline On-Time Performance Data ) |
| Departures Performed | Takeoffs made at an airport. (same as Completed Departures) ( Air Carrier Statistics ) |
| Departures Scheduled | Takeoffs scheduled at an airport, as set forth in published schedules. (same as Scheduled Departures) ( Air Carrier Statistics ) |
| Derailment | A derailment occurs when on-track equipment leaves the rail for a reason other than a collision, explosion, highway-rail crossing impact, etc. ( Railroad Accident/Incident Reporting System ) |
| A non-collision incident which occurs as a result of rolling equipment leaving the rail, or buses leaving the roadway, and for roll overs. Report all incidents regardless of severity. ( National Transit Database ) |
| Destination | For travel period trips, the destination is the farthest point of travel from the point of origin of a trip of 75 miles or more one-way. For travel day trips, the destination is the point at which there is a break in travel. ( Nationwide Personal Transportation Survey ) |
| Destination Of Trip | The place reported by a respondent as the destination of the trip. If more than one place is visited on the same trip, the place which is the farthest point from the origin is considered the destination of the trip. ( American Travel Survey ) |
| Destination State FIPS | The FIPS code for the destination state. (see FIPS) ( Air Carrier Statistics ) |
| Directly Operated | Transportation service provided directly by a transit agency, using their employees to supply the necessary labor to operate the revenue vehicles. This includes instances where an agency's employees provide purchased transportation services to the agency through a contractual agreement. ( National Transit Database ) |
| Displacement Tonnage | The weight, in tons of 2,240 pounds, of the vessel and its contents. Calculated by dividing the volume of water displaced in cubic feet by 35, the average density of sea water. ( Marine Casualty and Pollution Database ) |
| Distance Shipped | The distance between origin and destination for a shipment. For the distance shipped intervals table, the distance is calculated based on the great circle distance between the origin and destination ZIP Code centroids. All other distance-related data (i.e., ton-miles and average miles per shipment) are based on the mileage calculations produced by Oak Ridge National Laboratories. ( Commodity Flow Survey ) |
| Diverted Flight | A flight that is required to land at a destination other than the original scheduled destination for reasons beyond the control of the pilot/company. ( Airline On-Time Performance Data ) |
| Domestic Operations | All air carrier operations having destinations within the 50 United States, the District of Columbia, the Commonwealth of Puerto Rico, and the U.S. Virgin Islands. ( Small Air Carrier Statistics, Airline On-Time Performance Data ) |
| Doubled Bottom | A maritime vessel hull contruction technique which protects the bottom of a ship with an additional outer layer along the bottom of the ship, usually several feet away from the internal hull. ( Marine Casualty and Pollution Database ) |
| Doubled Hull | A maritime vessel hull contruction technique using an additional outer layer along the entire hull of the ship, usually several feet away from the internal hull. ( Marine Casualty and Pollution Database ) |
| Driver | A person who operates a motorized vehicle. If more than one person drives on a single trip, the person who drives the most miles is classified as the principal driver. ( Nationwide Personal Transportation Survey ) |
| An occupant of a vehicle who is in physical control of a motor vehicle in transport, or for an out-of-control vehicle, an occupant who was in control until control was lost. ( Fatality Analysis Reporting System ) |
| Driver Distracted | Indicates distracting events which may have influenced driver performance and contributed to the cause of the crash. Distractions can be both inside and outside the car. ( General Estimates System (NASS/GES) ) |
| Dun & Bradstreet Number | A unique nine-digit sequence issued by Dun & Bradstreet and used for identifying and keeping track of over 70 million businesses worldwide. ( Motor Carrier Management Information System (MCMIS) Census File ) |
| Duration Of Trip | Number of nights spent away from home on a trip and includes nights spent at the destination, nights spent en route and nights spent on side trips. It is possible for a trip not to involve an overnight stay from home; a traveler could take a trip of 100 miles or more and return on the same day. ( American Travel Survey ) |
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