Although the Prius looks relatively ordinary from the outside, this belies the sophisticated technology on the inside of the car. The "normal" exterior suggests Toyota’s desire to create instant acceptance for the car as a traditional five-seat family vehicle. In Latin the word prius means "to go before," and this car is in fact the first hybrid-powered car available for mass distribution and has already begun selling well in Japan. The Prius has significant advances in terms of fuel economy and emission over current gasoline cars. The two power sources include a 58-horsepower, 1.5-liter, four-cylinder engine, and a 40-horsepower electric engine. In congested urban areas the electric motor is the workhorse, and the car uses the gasoline engine when extra power is needed. A computer seamlessly alternates the power sources, only activating the gas engine when necessary. Because idling and low acceleration usually produce the greatest amount of emissions in a gas engine, the Prius employs the electric motor under these driving conditions. In fact, the Prius gets its best gas mileage in the stop-and-go traffic of a city. A unusually long wheelbase enhances handling, and low resistance tires help to produce an estimated gas mileage of 66 mpg.