Systems employing elastic materials suffer from hysteresis, and metal springs are too dense to be useful in many cases.Flywheels store energy in a spinning mass. Because a light and fast rotor is energetically favorable, flywheels can pose a significant safety hazard. Moreover, flywheels leak energy fairly quickly and affect a vehicles steering through the gyroscopic effect. They have been used experimentally in gyrobuses. Wind energy is used by sailboats and land yachts as the primary source of energy. It is very cheap and fairly easy to use, the main issues being dependence on weather and upwind performance. Balloons also rely on the wind to move horizontally. Aircraft flying in the jet stream may get a boost from high altitude winds. Compressed gas is currently an experimental method of storing energy. In this case, compressed gas is simply stored in a tank and released when necessary. Like elastics, they have hysteresis losses when gas heats up during compression. Gravitational potential energy is a form of energy used in gliders, skis, bobsleds and numerous other vehicles that go down hill. Regenerative braking is an example of capturing kinetic energy where the brakes of a vehicle are augmented with a generator or other means of extracting energy. Motors and engines
When needed, the energy is taken from the source and consumed by one or more motors or engines. Sometimes there is an intermediate medium, such as the batteries of a diesel submarine.Most motor vehicles have internal combustion engines. They are fairly cheap, easy to maintain, reliable, safe and small.
The right to this land is granted to the railway company through mechanisms such as easement. Watercraft are generally allowed to navigate public waters without restriction as long as they do not cause a disturbance. Passing through a lock, however, may require paying a toll. Despite the common law tradition Cuius est solum, eius est usque ad coelum et ad inferos of owning all the air above ones property, the US Supreme Court ruled that aircraft in the US have the right to use air above someone elses property without their consent. While the same rule generally applies in all jurisdictions, some countries such as Cuba and Russia have taken advantage of air rights on a national level to earn money. There are some areas that aircraft are barred from overflying. This is called prohibited airspace. Prohibited airspace is usually strictly enforced due to potential damage from espionage or attack. In the case of Korean Air Lines Flight 007, the airliner entered prohibited airspace over Soviet territory and was shot down as it was leaving. Safety
For a comparison of transportation fatality rates, see: Air safety statistics. Several different metrics used to compare and evaluate the safety of different vehicles. The main three are deaths per billion passenger-journeys, deaths per billion passenger-hours and deaths per billion passenger-kilometers. See also

Automotive acronyms and abbreviations
ISIRI 6924
Narrow-track vehicle
Outline of vehicles
Personal transporter
Propulsion
Single-track vehicle
Vehicular dynamics
Vehicular metrics


== References ==