Massachusetts overwhelmingly voted in favor of what has been described as the most expensive ballot measure in the state’s history: an extension of a “right to repair” law first signed in 2013.

The referendum will require automakers to open up data generated by vehicles to a broader set of constituents. Namely, it will force car companies to allow independent dealerships, auto repair shops, and mechanics to have access, as authorized by car owners.

The requirement is slated to take effect in model year 2022. While the earlier law required the sharing of mechanical data, the new proposal compels carmakers to include the sharing of telematics, driving, and diagnostics data, the kind that increasingly gets transmitted wirelessly from cars to automakers.

Advocates of the proposal argued that such information is essential for third-party businesses to continue providing maintenance and repair services. Opponents alleged that the new law, especially adopted on short notice, would present cybersecurity, hacking, and privacy risks.

The Massachusetts Right to Repair Committee, an industry coalition, declared victory after 9 p.m. ET, an or so hour before the Associated Press projected the ballot measure’s passage. With 86% of precincts reporting, the proposal has so far won over three-quarters of voters.

“The people have spoken—by a huge margin—in favor of immediately updating right to repair so it applies to today’s high-tech cars and trucks,” Tommy Hickey, the director of the Yes on 1 coalition, said in a statement. “Automakers were trying to corner the market on car repairs, but the voters stopped them.”

The Coalition for Safe and Secure Data, a group that opposed the proposal, released its own statement alleging that local repair shops’ right to access essential data was “already enshrined in Massachusetts law.”

“Today’s vote will do nothing to enhance that right—it will only grant real-time, two-way access to your vehicle and increase risk,” the oppositional group said. “At no point did the Yes side provide any credible arguments as to why national auto parts chains need this information to service your vehicles.”

The right to repair is a contentious issue. Corporate opponents range from iPhone maker Apple to tractor-maker John Deere, which prefer to maintain tight control of their products. As carmakers like Tesla and GM add autonomous driving features to their vehicles, the issue has grown more heated.

Kyle Wiens, cofounder of iFixit, a DIY community, praised the ballot measure’s passage. “It’s your car. You should be able to fix it yourself,” he said in a post on Twitter.

“This will be the most advanced #RightToRepair law in the world, opening wireless automotive diagnostics and unleashing a world of possible apps,” Wiens added.