Greater operating efficiency because HEVs use regenerative braking, which helps to minimize energy loss and recover the energy used to slow down or stop a vehicle;
Lighter engines because HEV engines can be sized to accommodate average load, not peak load, which reduces the engine's weight;
Greater fuel efficiency because hybrids consume significantly less fuel than vehicles powered by gasoline alone;
Cleaner operation because HEVs can run on alternative fuels (which have lower emissions), thereby decreasing our dependency on fossil fuels (which helps ensure our national security);
Lighter vehicle weight overall because special lightweight materials are used in their manufacture.
Hybrid electric vehicles are very cost-competitive with similar conventional vehicles, and any cost premium can be offset by overall fuel savings and tax incentives. Some states even offer incentives to consumers buying HEVs.
Auto manufacturers are making HEVs that match the performance, safety, and cost of conventional vehicles because they know that these are the three most important variables to consumers. And by combining gasoline with electric power, HEVs have the same or greater range than vehicles powered by traditional combustion engines. An HEV is two times more efficient to operate than a conventional vehicle. Behind the wheel, drivers of HEVs will experience performance that is similar to, or better than, that of conventional vehicles. More important, HEV performance is available now, and so consumers can choose a cleaner-driving vehicle today. U.S. Dept.of Energy