China issued a proposed regulation on Thursday making road tests of self-driving vehicles legal nationwide.

It allows local governments to open public roads for self-driving vehicles tests and approve and issue road test car plates.

The regulation, issued by the Ministry of Public Security, Ministry of Industry and Information Technology and Ministry of Communications, will take effect May 1.

The rule came after Baidu boss Robin Li test drove the company's autonomous vehicle on Beijing's public roads last July, causing controversy as there were no rules regarding such a test.

Opening more public roads for tests signifies China is taking another step to support the self-driving vehicle industry.

In March, Shanghai and Beijing issued the country's first batch of road test licenses. Authorized operators are allowed to use public roads for testing self-driving vehicles, a precondition for self-driving vehicles to replace human-driven vehicles.

Though seen as the future of the automobile industry, self-driving vehicles encounter many legal and ethical questions over safety.

In March, a tragic accident happened in Arizona, US, where an Uber self-driving car struck and killed a woman crossing the street.