The technology largely lay dormant for almost a century until Toyota introduced the Prius hybrid to the U.S. market in 2000, on the heels of the Honda Insight hybrid’s debut in 1999. But it was the second-generation Prius introduced in 2003 as a compact hatchback that made the car a commercial success and a poster child for hybrids for the past quarter century. Even with the recent rise of battery electric vehicles (EVs), hybrid sales have not only stayed steady but gained ground. They’ve become so popular that the latest generation of the Toyota RAV4 and Camry, two of the bestselling vehicles in the U.S., are available only as hybrids.

What Is a Hybrid Vehicle?

Hybrid is used to describe any vehicle that uses two or more types of power, such as an electric bike that uses both human pedal power and an electric motor for propulsion. Hybrid-electric passenger vehicles use an internal combustion engine (ICE) like all gas-powered vehicles do but add an electric motor to assist with propulsion and create a more energy-efficient powertrain.

Another key component of a hybrid vehicle is a large traction battery that supplies power for the electric motor. An important distinction between many hybrid vehicles and EVs is that a hybrid’s battery can’t be charged by an external power source. An exception is plug-in hybrid electric vehicles (PHEVs) that can be connected to an external power source to charge the battery.

PHEVs occupy a middle ground between conventional hybrids with their electric motor and gas powertrain combination and pure battery electric vehicles that can only be connected to a power source to recharge the battery. When a PHEV’s electric-only range is depleted, it operates like a regular hybrid. The primary benefit of PHEVs over regular hybrids is they can operate in electric-only range for between 20 and 60 miles, depending on the model. If PHEV drivers only make short trips and regularly charge the battery, they may only have to buy gas for longer journeys.

Types of Hybrid Vehicles

While all hybrids contain a gas engine, electric motor, and traction battery, there are different types:

With parallel hybrids, the gas engine and electric motor supply power to drive the wheels through a common drive shaft, either together or independently. Most use either a traditional multi-speed automatic transmission or a continuously variable transmission (CVT).
Series hybrids, also called extended-range EVs (EREVs), use an electric motor to drive the wheels while a smaller gas engine serves as a generator to power the electric motor and charge the hybrid battery. EREVs have the advantage of being able to operate both like a traditional hybrid and a PHEV since they can be powered by the gas engine for long periods, and the battery can be connected to an external power source to recharge. They also have a larger battery, giving them more electric-only range than PHEVs, but this also makes EREVs more expensive. So far, only a handful of EREV-powered models are expected to be available in the U.S. in 2026.
Power-split hybrids, also known as series-parallel hybrids, have become common in high-volume hybrid vehicles such as the Ford Maverick, Toyota RAV4, and Subaru Forester (all based on Toyota’s design). These vehicles use what’s known as a planetary gearset that blends power from the gasoline engine and electric motor (or motors) at various speeds and sends it to the wheels. Power-split hybrids don’t use a conventional automatic transmission with fixed gear ratios or a belt-driven CVT. Instead, they direct power to the wheels via an electronically controlled CVT that constantly alters gear ratios to improve efficiency. The Honda Accord, Civic, and CR-V almost always function in series, but at certain speeds the engine connects to the wheels (Chevy’s Volt also worked like this).
Finally, mild hybrids have a smaller battery and electric motor, usually a 48-volt generator, than other hybrids that together can’t supply enough power to propel a vehicle on its own. Instead, mild hybrids assist the gas engine and run electrical accessories to improve overall efficiency but don’t increase fuel economy nearly as much as a full hybrid.