Dead mileage, dead running or dead heading in public transport and empty leg in air charter, is when a revenue gaining vehicle operates without carrying or accepting passengers, such as when coming from a garage to begin its first trip of the day. In this case the vehicle is said to be deadheading.
Similar terms in the UK include ECS (Empty coaching stock) move or DIT (Dead in tow).
The term deadheading also applies to the practice of allowing employees of a common carrier to use a vehicle as a non-revenue passenger. For example, an airline might assign a pilot living in New York to a flight from Denver to Los Angeles, and the pilot would simply catch any flight going to Denver, either wearing their uniform or showing ID, in lieu of buying a ticket. Also, some transport companies will allow employees to use the service when off duty, such as a city bus line allowing an off-duty driver to commute to and from work, free.
Additionally, inspectors from a regulatory agency may use transport on a deadhead basis to do inspections such as a Federal Railroad Administration inspector riding a freight train to inspect for safety violations.
Dead mileage routinely occurs when a bus route starts or finishes in a location away from a bus garage or out-station, and the start or end of a shift requires driving the bus to and from the garage out of service. Dead mileage can also occur in cases where shift-break parking has to be undertaken in terminals away from the service route.
Dead mileage incurs costs for the operator in terms of non-revenue earning fuel use, wages, and a reduction in the use of the driver's legal hours of driving.
Operators will often reduce dead mileage by starting or finishing the first or last service of the day, or shift, at a garage along the route, a so-called part service or part route. Dead mileage may also be reduced by the operation of routes specifically timed and routed to facilitate bus movements rather than passenger need.
Dead mileage has increasingly become an issue with privatised competition for bus services, most notable with the privatisation of London bus services, where competing operators have to factor on the cost of dead mileage when bidding for specific routes away from their main garages. This is exacerbated by not being allowed to operate a service that may match the dead mileage route. This can be lessened to an extent by tendering routes in groups of sufficient size to justify opening/renting new garage space.
Often operators will come to an arrangement to share garage facilities to reduce dead mileage.
Some air charter companies are leasing out their planes at a lower rate for those empty leg flights to reduce the cost or profit from those originally non-revenuing flights.