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:''See also Global Hybrid Cooperation for the General Motors/DaimlerChrysler/BMW hybrid vehicle technology often called "Dual-Mode"'' A dual-mode vehicle is a vehicle that can run on conventional road surfaces or a dedicated track known as a "guideway". Dual-mode vehicles are commonly electrically powered and run in dual-mode for power too, using batteries for short distance and low speeds, and track-fed power for longer distances and higher speeds. Dual-mode vehicles were originally studied as a way to make electric cars suitable for inter-city travel without the need for a separate engine. More recently, starting in the 1990s, a number of dual-mode mass transit systems have appeared, most notably a number of rubber tyred trams and guided buses. ==The problem== The modern automobile is one of the most flexible forms of transit invented. It can operate in almost any weather, is instantly available on demand, carries hundreds to thousands of pounds of cargo and drives directly from origin to destination. The modern internal combustion engine is able to provide power with relatively good efficiency over a wide range of power demands. The fuel is simple to store and transport, is energy dense, and can re-fuel a vehicle in moments. This combination of features means that a car can be used to travel over any sort of distance, from inter-city trips at low-speed for shopping, to inter-city trips at high-speeds to visit distant relatives. No other form of transit offers the same variety of capabilities. That said, there are numerous reasons why automobiles are not as efficient as they could be. Engines are normally sized to provide the acceleration performance or load-bearing capacity needed for operations in a city, which is far too much power than would be needed for operations on an expressway at high speeds. Suspension loads vary relative to the square of speed, so cars have systems able to deal with loads at highway speeds when a much lighter-duty system would be suitable for city driving. Electric motors offer all the advantages of engines, and more so, but their "fuel" (batteries) are only suitable for short and infrequent service. If one was able to design cars for specific purposes, they can be tuned for much greater efficiency. The vast majority of car trips are short and low-speed; cars designed for this role can be far more efficient than the generalist vehicles generally used. However, the low ownership of specific-purpose vehicles, like motorcycles, is a good indication of the basic problem: people don't want to have to buy two vehicles to serve a single need: transportation. This has limited other forms of transit to specific roles: aircraft are used for long-distances, trains for inter-city freight and travel, and electric vehicles for known routes where power can be provided at all times. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dual-mode vehicle」の詳細全文を読む スポンサード リンク
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