Hertz recently signed a deal to buy 65,000 electric vehicles from startup Polestar over five years. The city of Houston, meanwhile, has purchased about 100 electrical appliances to replace aging gas-powered cars, and Amazon wants to put 100,000 battery-powered delivery trucks into circulation.

Wondering why these cars are so popular with fleets? Let’s take a walk.

Initially, the adoption of electric vehicles can boost a company’s sustainability, which, in turn, could help brand image. However, the benefits of electric vehicles for fleets go far beyond marketing.

Wakefield Research surveyed 300 fleet managers and found that 44% believed electric vehicles would reduce fuel costs. Although charging an electric vehicle is not free, it is currently cheaper to fill a battery than a gas tank.

Electric vehicles are potentially easier to maintain. With combustion engines, you not only have to worry about gasoline, but also oil and spark plugs, two issues unrelated to electric cars. Almost all combustion vehicles need transmission fluid, while many (but not all) EVs skip transmissions completely, rendering fluid unnecessary.

Moving parts are also prone to failure and repairs can be expensive. If a transmission fails, you’ll have to shell out thousands of dollars to replace it. Cracked cylinder heads and rusted exhaust systems, among other things, also cost considerable sums to repair. Ultimately, Wakefield Research reports that 85% of current electric vehicle owners said traditional vehicles cost more to maintain.

With fewer moving engine/transmission parts, electric cars can ease potential headaches. Still, that doesn’t mean EVs offer a free ride. The initial costs of electric vehicles are generally higher. And although batteries often last for hundreds of thousands of miles, they lose capacity over time and are expensive to replace. Charging times can also span hours.

Still, all told, electric cars offer an attractive option for fleet managers.