NHTSA Asks States to Limit Autonomous Cars

States should permit self-driving vehicles on public U.S. roads only during supervised tests by vetted organizations, the National Highway Traffic Safety Administration advises.

The agency's preliminary policy statement says autonomous vehicles represent an "enormous" safety potential. But it cautions that the technologies required aren't yet developed enough to allow the general public to operate self-driving cars.

NHTSA says it's too soon to even determine the feasibility of vehicles that can operate automatically under all driving conditions. It suggests states and vehicle developers view emerging technologies as a "continuum of vehicle control automation."

The agency describes five echelons of vehicle automation:

• Level 0. Leaves the driver with sole responsibility for all primary vehicle controls at all times. The vehicle may signal such risks as a vehicle in the driver's blind spot, but it takes no action.
• Level 1. Certain individual functions, such as stability control or braking, are automated. But the technology never assumes driving responsibility. Nor does it allow operators to safely remove their hands from the steering wheel and feet from the brake or accelerator pedals simultaneously.
• Level 2. Integrates some features lane keeping and adaptive cruise control, for example and allows operators to briefly remove their hands and feet from the controls. But Level 2 systems may relinquish control suddenly and without warning, so operators must continuously monitor driving conditions and be ready to take over at any moment.
• Level 3. Provides limited self-driving capabilities that allow the driver to cede responsibility for all safety-critical functions under certain conditions. The system gives the operator sufficient warning to resume control if it cannot maintain automatic operation.
• Level 4. Vehicles at this level perform all safety-critical functions for an entire trip. The "driver" provides nothing more than destination or navigation input. Level 4 vehicles assume full responsibility for vehicle operation and could function with no occupants aboard.

NHTSA's rulemaking activities so far have applied only to Level 0 technologies. The agency says it expects to decide within the next year whether to issue standards for such Level 1 capabilities as automatic braking. It also has begun or is planning research on Levels 2, 3 and 4 systems in three areas: human factors, system performance and electronic control system safety.