Hybrid is a term used referring to dual-fuel cars. It means your car could be run by two machines or engines. Hybrid cars could have two combustion engines, that is; one is run using petroleum and the other is by diesel. The engine to be used by the car will depend on your modifications. You just need to click the switch if you want it to run by diesel or petroleum. Though this is not that environmentally friendly car, it could address the issue on the shortage of petroleum and diesel in different gasoline stations. Other hybrid cars switch between electricity driven motor and conventional combustion engine which is preferable to the former. The combustion engine could be run by biodiesel which is preferable to the petroleum diesel.

In England, there are car rental companies that promote hybrid cars. One of those companies is the Go Green Car and Van Rental Company, the first British car rental company. This company tried to respond in the uprising demand for environment friendly cars. They want to reduce the company's environmental impact while meeting the needs of their consumers. They offer environment friendly diesel engine cars (Toyota Prius hybrid cars) which emit lower amount of carbon oxides in the air compared to other cars. The Prius cars run in two ways; by electricity driven motor and by combustion engine motor. The Go Green Company claimed that Prius is their most environment friendly cars and that they would continue to invest on it. Green cars could cover more distance than any other cars, which means greater efficiency, that's why they continue investing on it.

Other hybrid cars are termed "flex-fuel" which runs on 85% ethanol and 15% gas or E85 mixture. This emits less amount of carbon dioxide which is also being absorbed by the plants. It is true that hybrid cars cost more than conventional cars. But in terms of energy efficiency, hybrid cars are more efficient especially in long distance driving. The problem with hybrid cars which are "flex-fuel" is that only few filling stations sell E85. If E85 would be sold in many filling stations, those environment friendly cars will not have a problem entering and prevailing in the market since the world now demand for environment friendly cars.

Nissan, Honda, Toyota, and Ford are among the car companies that sell hybrid cars today. The cars that they developed were included in the list of the greenest vehicles. The American Council for an Energy-Efficient Economy (ACEEE) created a numeric standard in measuring the value of the car's environment friendliness. This numeric standard is called The Green Score and is the basis in deciding which car is environment friendly and which is not. The Go Green Car and Van Rental Company, among the other rental companies that promotes environmental protection, support the greenest cars that are available in the market. Renting cars in Go Green is really going green since you are supporting an environment loving company.