Although a relatively new addition to the car market, hybrids are rapidly growing in popularity and today, most car manufacturers have at least one hybrid to offer their customers. The hybrid combines two power sources to hopefully provide more efficient and cleaner power to the vehicle, saving the driver on fuel costs. A popular combination of power source, those used by Toyota in their Prius Hybrid and other manufacturers in some of their hybrid models, is a combustion engine and an electric motor. The combustion engine can provide substantial power when needed such as for when driving on a highway whilst the electric motor, which is powered by a battery recharged by the combustion engine, is ideal for use at slower speeds or when the car is idling. When bursts of extra power are needed for such manoeuvres as overtaking, both the combustion engine and the electric motor can be used together, giving more power than a combustion engine the same size could usually provide. This means that hybrids not only can be fuel efficient if used right but can also be as powerful if not more powerful than a more traditional car which runs on a combustion engine only. The modern hybrids do not differ from the traditional cars in comfort, luxury or even safety features and some may even afford more features than traditional cars. Not only are hybrid cars becoming more popular to buy but rent hybrid car options are also becoming more popular. It is perhaps understandable that the rental of hybrids would increase proportionally to the number of sales as often a buyer may rent the model of vehicle they intend to buy, before actually buying one, ensuring that what they buy is what they want however, hybrids seem to be becoming more popular with other rental customers also. Obviously when people rent a car, they are just as concerned about the cost of running that car as they would be in the cost of running a car they owned and so, they too want fuel efficiency in the car they rent. Probably the largest number of car renters are vacationers because rather than using up precious vacation days driving to their chosen vacation destination, prefer to fly to the destination and then rent a car there once they have arrived. This also saves them wear and tear on their car plus means that they will usually arrive at their destination relaxed and not over tired from an extended drive. Other people that rent cars are those people that want to spend a day out but find that their own car is not suitable for what they intend to do. Perhaps they need a larger car in order to take out the extended family or perhaps they need an SUV to do some off-road driving which their family car would not cope with. Whatever the reason or for however long the rental period, a car renter must be concerned with the cost of fuelling their rented vehicle and so hybrids are becoming the popular choice for those renters.