The U.S. National Highway Traffic Safety Administration (NHTSA) on Friday held the first of two public hearings to get input as it writes policy guidance for states, automakers and tech companies about when and how autonomous vehicles should be allowed on U.S. roads. It has vowed to complete guidelines by July.

NHTSA “should not bind itself to arbitrary, self-imposed deadlines at the expense of robust and thoughtful policy analysis,” said Paul Scullion, safety manager at the Association of Global Automakers, a trade group representing Toyota Motor, Nissan Motor, Hyundai Motor and other major foreign automakers. “NHTSA should instead consider the development incrementally.”

NHTSA Administrator Mark Rosekind said Friday the agency must move quickly, noting cars with significant self–driving features like Tesla Motors’ autopilot function are already on the road.

Without NHTSA action “people are going to just keep putting stuff out on the road with no guidance on how do we do this the right way,” Rosekind said.

Major automakers and technology companies led by Alphabet’s Google unit are racing to develop and sell vehicles that can drive themselves, but they have complained that state and federal safety rules are impeding testing and ultimate deployment of such vehicles.

Google (GOOG) has logged more than 1.5 million miles of autonomous vehicle testing.

Several speakers said self–driving vehicles are not ready for public use, citing their inability to operate in snow and other technical challenges. “Self–driving robot cars simply aren’t ready to safely manage too many routine traffic situations without human intervention,” Consumer Watchdog privacy project director John Simpson said at the hearing Friday.

One commentator suggested that states should give self–driving cars “graduated driver licenses” before allowing them on the road. Another warned autonomous vehicles could be used as drone-style weapons.

For more about self-driving cars, watch:

In December, California proposed state regulations that would require all autonomous cars to have a steering wheel and throttle and brake pedals when operating on state roads. A licensed driver would need to be in the driver’s seat ready to take over in the event something went wrong.

Google opposes California’s proposal and has called on Congress to approve new legal authority for NHTSA to allow fully autonomous vehicles on U.S. roads. NHTSA plans another public meeting at Stanford University on April 27 on its autonomous vehicle guidance.