When General Motors paid $581 million for self-driving car startup Cruise in 2016, it was one of the biggest bets by a company in the nascent business. Two years later, Cruise is a case study of the perils and the promise of self-driving car technology.

Despite some advances, Cruise’s vehicles being tested in San Francisco are still repeatedly involved in accidents, or near-accidents where a person has to grab the wheel of the car to avoid a collision. As a result, despite promises that autonomous vehicles could be available in the next few years, it is likely to be a decade before the cars come into wide use in major cities, according to a person with direct knowledge of Cruise’s technology.