Getting a car to drive on South Beach may soon be about as easy as ordering a pizza.

The city of Miami Beach is launching a program that will allow tourists and residents to rent sedans, SUVs and eventually electric cars on an as-need basis for as brief and cheap as $9 an hour.

The service, provided through Hertz On Demand, kicks off Tuesday when 20 cars will become available in eight parking garages located mostly in South Beach. The city’s fleet could eventually reach 100 cars.

“This is a really great reason not to have a car on Miami Beach,” said Saul Frances, the city’s parking director. “You really don’t need one with this program because you can just pick up a car at one of our garages.”

Here’s how Hertz On Demand works:

Customers register for free at www.Hertzondemand.com, which they then use to rent a car at rates ranging from $9 to $15.75 per hour or $63 to $170 a day, according to the city. The bill is charged to a credit card and the price of gas and insurance is included in the rate, though accidents come with a $250 deductible.

After registering, members get a swipe card, which is scanned by a device on the windshield to open the vehicle. The keys and a gas card are already inside. Cars can be picked up and returned on the upper levels of the city’s parking garages.

There are a couple drawbacks: Returning the car with less than a quarter-tank of gas, losing a key or gas card, or changing a rental time less than four hours before scheduled will result in a fine. No smoking or pets. And parents must bring their own child seats.

Hertz has established the same program in a dozen American cities, and more than 40 universities, including Florida International University, but Miami Beach says the program is the first municipal car share service in Florida.

The city is also touting the initiative as a traffic-reducing, environmentally friendly program, though for now it’s debatable how much 20 available vehicles will affect either.

But for residents who don’t want or can’t afford the maintenance or insurance that comes with a car, or for tourists who’d rather not spend on long taxi rides or car rentals, the program could be a convenient way to get around when need be. And the city will see a small windfall.

Miami Beach will eventually bring in about $84,000 a year on a parking space rental fee charged to Hertz if its fleet hits 100 vehicles, plus a small cut of Hertz’s profit starting in year three of the deal, which was approved in 2008.

But city spokeswoman Nannette Rodriguez said there’s a broader goal.

“Are we going to make a lot of money off of this? Probably not,” she said. “But it’s a way to continue to make improvements and have alternative modes for getting around.”