New cars would be required to have technology to stop drunk people from driving under a mandate Congress approved as part of the sweeping infrastructure bill — a step that could significantly reduce one of the leading causes of crash-related deaths.

More than 10,000 people died in crashes involving an alcohol-impaired driver in 2019, according to the National Highway Traffic Safety Administration. Campaigners against drunken driving say the new technology would bring that number down dramatically — and that it’s needed at a time when once-declining death rates have plateaued in the past decade.

“This technology will essentially eliminate drunken driving,” said Alex Otte, president of Mothers Against Drunk Driving.

The mandate is among several road-safety provisions in the infrastructure bill. It also calls on NHTSA to require automatic braking for cars and the largest trucks, for a revamp of vehicle safety ratings and requiring in-vehicle alerts to help stop children from being left in hot cars. The bill also seeks to address the design of roads, providing money for designs that prioritize the safety of pedestrians and cyclists.

Of the measures in the bill, the drunken driving technology provision could have the greatest potential to save lives.

A recent study by the Insurance Institute for Highway Safety concluded the technology could reduce deaths by 9,400 people a year if widely deployed. Such a reduction would likely take years to materialize, but under a timeline set out by lawmakers, the technology could be required in new vehicles as soon as 2026.

The bill calls on NHTSA to finalize rules for the technology within three years, then give automakers at least two years for production. It also gives officials room to conclude that timeline isn’t feasible, which could prompt a delay. NHTSA in the past has struggled to meet congressional deadlines.

Many states already require breathalyzer interlocks for drunken-driving offenders, but experts expect the approach implemented under the mandate in the bill would be different.

“It’s entirely passive,” Otte said. “For those being safe, it won’t change the relationship with their car in any way.”

NHTSA has been working with the Automotive Coalition for Traffic Safety (ACTS), an industry group, since 2008 on systems to discretely detect alcohol on drivers’ breaths or in their blood. The Driver Alcohol Detection System for Safety project has been testing sensors in recent years, including with a Virginia transportation company, and hopes to have a road-ready approach by 2024.

Another option would be to rely on cameras that monitor drivers for signs they are impaired, building on systems that automakers are using to ensure people relying on driver assistance technologies don’t lose concentration.

The Alliance for Automotive Innovation, another industry group, has said it favors the blood or breath sensors, raising concerns in a January letter to NHTSA that a camera-based system would not be reliable enough and could provoke a backlash among car owners.

“New technologies, especially those intended to provide a safety benefit, are subject to much scrutiny,” wrote Scott Schmidt, the organization’s vice president for safety policy. “When such technologies impact the autonomy of the driver, they require broad public acceptance.”

John Bozzella, the chief executive of the alliance, said in a statement Tuesday he appreciated that the bill gave regulators the flexibility to assess the best technological solution.

Schmidt pointed to the 1970s, when safety regulators required that cars not start if drivers weren’t wearing seat belts. It was so unpopular that Congress quickly outlawed the approach.

Rob Strassburger, chief executive of ACTS, said that experience serves as a cautionary one for his team, which has been seeking to ensure consumers will accept anti-drunk driving technology. The group says its research indicates about three-quarters of drivers are on board.

“We’re starting in a very good place,” Strassburger said. “Obviously we need to win over a few more folks.”

Strassburger said the group’s technology is expected to be ready within the timeline spelled out by Congress. While NHTSA has long been involved with its development, it’s not clear how quickly the agency might work to turn the congressional mandate into a binding rule.

During a briefing on the infrastructure bill Tuesday, Carlos Monje Jr., the Transportation Department’s undersecretary for policy, said only that the government would work with the industry and advocates on a process to “get it right.”

While road safety advocates say they are pleased with many of the provisions in the bill, Cathy Chase, executive director of Advocates for Highway and Auto Safety, said some measures didn’t go far enough or were written in a way that could mean some requirements could be delayed.

For example, midsized trucks — the kind increasingly being used to make deliveries in residential areas — were not included in the automatic-braking requirement and the bill only calls for alerts for drivers to check back seats, rather than systems to detect whether a child has been left behind.

“It’s a step forward for safety, but unfortunately, there are some loopholes that give us great concern about delivering the final product,” Chase said.