The U.S. Department of Transportation's National Highway Traffic Safety Administration (NHTSA) has released a policy that outlines guidelines for driving and testing vehicles with different levels of autonomous driving capabilities.

With Google testing autonomous vehicles, and a number of automakers working on different types of autonomous vehicle technologies, NHTSA developed the guidelines to ensure safe testing of autonomous vehicles and related technologies.

Although the guidelines apply to testing, at this time NHTSA says states should not authorize anyone to operate self-driving vehicles in situations other than testing. The organization said there are a number of technical and driver-related issues that companies building, and testing, autonomous vehicles must address before they are safe to operate on U.S. roads.

The policy document from NHTSA also includes a description of different levels of automation (0 through 4, with 0 being no automation and 4 being “Full Self-Driving Automation) and guidelines for states than want to allow automakers and other companies to test autonomous vehicle technologies. They include ensuring the “driver” of an autonomous vehicle knows how to operate it, that states require that companies testing these technologies limit the risk to other drivers, limit the road conditions under which companies and organizations can conduct tests, and that states establish reporting requirements for autonomous vehicle testing.

For the vehicles themselves, NHTSA says states should require that the control process in autonomous vehicles for switching from self-driving to driver control is safe, simple and timely; that self-driving test vehicles can detect and record malfunctions and inform the driver if something is wrong; that the autonomous vehicle technologies don’t disable any federally required safety systems; and that self-driving test vehicles record information on automated control systems during a crash or loss of control of the vehicle.

You can read the complete policy here.