Cruise, the self-driving technology company backed by General Motors and Honda, is now testing driverless cars in San Francisco.

A video released on Wednesday shows the moment one of Cruise's self-driving car prototypes heads down a public road for the first time with no one behind the wheel.

Cruise in October joined a handful of companies to have received a permit from the California DMV to test prototypes on the state's roads without a safety driver behind the wheel. Others include Google-backed Waymo, Amazon-backed Zoox, China's AutoX, and Nuro, a self-driving startup founded by ex-Google engineers.

What sets Cruise apart is its choice of San Francisco as its center of development. Whereas rivals are developing their self-driving systems in relatively quiet surroundings with wide streets, Cruise has a much tougher environment to deal with. According to the company, its prototypes encounter around 3,200 cut-ins by other drivers, 3,000 double-parked cars, and hundreds of cyclists each and every week.

Cruise self-driving car prototype

Cruise self-driving car prototype

Getting up to this point has taken the company five years and over two million miles worth of real-world testing. And just to be safe, there's still an operator in the passenger seat for monitoring purposes. This person has access to a switch that can stop the vehicle in case of an emergency. It's possible Cruise is also able to remotely control the vehicle, though the company hasn't said if this is in fact the case.

Cruise's prototypes rank at Level 4 on the SAE scale of self-driving capability, as the cars are limited in the areas in which they can operate on their own. The final goal is Level 5, where a self-driving car is able to operate at the same level as a human driver. While Level 5 might be a decade or more away, companies plan to start offering commercial services involving Level 4 self-driving cars.

In January, Cruise unveiled a self-driving shuttle called the Cruise Origin that the company said would enter a limited service in 2021, likely in San Francisco. Cruise in November also said it would trial an automated delivery service with Walmart starting in early 2021. The delivery service will cover parts of Scottsdale, Arizona.

The leader in this field remains Waymo which has been offering an automated taxi service covering parts of Phoenix, Arizona, for more than a year. The service was originally limited to who could use it but in the past couple of months has been opened up to the public.