China has issued a temporary ban on the highway testing of autonomous cars. According to Bloomberg, the country’s auto regulators have warned automakers to keep their autonomous vehicle testing off highways until official rules are in place.

China’s Ministry of Industry and Information Technology is working with law enforcement to create uniform regulations for self-driving testing. The time frame of when those regulations will be finalized is currently unknown, though.

This temporary ban could affect Volvo, which wanted regular citizens behind the wheel of autonomous vehicles on public Chinese roads. In addition, the ban could stifle the growth of China’s own Chongqing Changan Automobile Co. The company’s self-driving car, outfitted with radar and cameras, made a 1,200-mile trek in the country this past April.

There has been increased scrutiny on autonomous car technology worldwide since federal regulators launched an investigation last month into a fatal Tesla Model S crash involving Autopilot from this past May.