In the long term, however, a more formal system will be needed to regulate so-called autonomous vehicles, or AVs. The technology raises a slew of questions that aren’t covered by existing rules governing motor vehicles, like: Should autonomous cars be clearly marked? Should they be allowed to operate without anyone inside? Can individuals own them, or should fleets of AVs be shared? Do their operators need a license? Should they be held to higher efficiency standards than traditional vehicles?

When the wheels of the state’s first self-driving car hit the pavement this month in Boston, they did so under provisional rules issued by Mayor Martin J. Walsh and Governor Charlie Baker.


On Thursday, two state lawmakers — Representative Tricia Farley-Bouvier, a Pittsfield Democrat, and Senator Jason Lewis, a Winchester Democrat — offered possible answers to some of those riddles, unveiling a measure that would set statewide rules for the testing and use of autonomous vehicles.

Like other officials, they are wary of falling behind the pace of the technology, resulting in an after-the-fact debate like the one about how to regulate ride-hailing firms such as Uber. In that case, legislation came only after the services had become widely popular.

But autonomous-car companies warn that too little is known about how the vehicles will be used to write a useful and lasting set of rules.

In a salvo that could be a precursor of regulatory fights to come, Cambridge-based startup nuTonomy Inc. — the only Massachusetts company actively testing self-driving cars — ripped apart the bill’s details in a letter to the Globe Friday, saying Lewis and Farley-Bouvier want to “micromanage” the nascent industry in a way that would stifle innovation.

Among other provisions, the bill would mandate that all self-driving cars weighing under 8,500 pounds be zero-emissions vehicles, and require their operators to pay the state 2.5 cents for every mile they travel. Only freight and emergency autonomous vehicles could drive more than a mile without a passenger.


NuTonomy’s chief counsel, Matthew Wansley, wrote that the law would make Massachusetts the only state in the country to impose a special tax on the vehicles.

“In the short term, the. . . tax would spur an exodus of companies currently developing and testing AVs in the Commonwealth, erasing an opportunity for economic development and diminishing our reputation as a leader in innovation,” Wansley wrote. “In the long term, the AV tax would have the perverse effect of punishing Bay Staters for using a safer form of transportation.”

The company also said that while it uses zero-emissions Renault ZOEs as test vehicles, requiring all self-driving vehicles to be electric would slow their development, limit their use for long-distance trips, and make them even less affordable than traditional cars.

It also objected to the bill’s ban on self-driving vehicles traveling more than a mile without a passenger inside.

Lewis, the bill’s cosponsor, has said the provision was intended to prevent empty “zombie cars” from circling endlessly instead of parking, which could worsen traffic. But Wansley cautioned that the rule would effectively prevent on-demand ride-hailing services from using AVs.

Dan Adams can be reached at daniel.adams@globe.com.