California’s DMV requires — in new rules which will take effect September 16 — that, when necessary, a driver must be able to take “immediate physical control” of any vehicle on public roads. This process has traditionally involved a steering wheel and brake and accelerator pedals, which could be a setback for Google’s self-driving car, that does not include these parts. While Google said that it will add them for testing purposes, it is unclear what the company will do in the future.

“With these additions, our safety drivers can test the self-driving features while having the ability to take control of the vehicle if necessary,” said Courtney Hohne, a Google spokeswoman.

However, the goal of the car is still a completely autonomous vehicle with no need for human intervention. Liability has become a large issue for the company since, in the case of an accident, no human would actually be responsible.

“The company that designed the technology might be targeted, along with the manufacturer, the car’s owner and any passengers who were riding in the vehicle at the time of an accident,” reports The Wall Street Journal.

“The bump in the road shows how far Google has to travel to get fully autonomous cars on city streets and highways,” notes WSJ. “The technology has to maneuver a host of obstacles, including acceptance by the general public and the issue of liability when accidents happen.”

Google is making about 100 of the prototype autonomous vehicles, which it plans to test on private roads starting next month.