Semi trailers and other heavy-duty vehicles in the USA would be required to come standard with automatic emergency braking (AEB) under a new rule proposed by the Biden administration this week.

The announcement followed a similar rule for all new passenger vehicles proposed last month and is part of a larger effort to slow the increase in fatal traffic crashes in recent years.

The new rule would require heavy vehicles that weigh 4.5 tonnes to be equipped with AEB to automatically apply the brakes when a crash is imminent.

The system would be required to bring a vehicle to a complete stop at speeds as low as 10km/h and as high as 80km/h, the US National Highway Traffic Safety Administration (NHTSA) said in its statement.

“We have been focused on this rule making really for many, many years,” NHTSA chief counsel Ann Carlson said at a press briefing.

Making AEB standard in all vehicles, both passenger and commercial was included as part of the Bi-partisan Infrastructure Law, which passed  the US congress in late 2021.

Supporters of the proposal say it is an important step toward the broader goal of improving road safety and reducing the number of vehicle crashes annually.

According to the NHTSA, there are approximately 60,000 rear-end crashes a year  in the USA involving a heavy vehicle hitting another vehicle.

Under the proposed rule, the agency estimates 19,118 crashes would be prevented,  and say that up to 155 lives could be saved as well as preventing 8,814 injuries annually.

After a 60-day public comment period, NHTSA says it will analyse the responses and make any necessary changes, a process that could take some months.

Carlson said she expects the final rule to go into effect sometime in 2024, at which point a phase-in period  will come into affect off for truck manufacturers.

For heavy duty Class 7 and 8 trucks, which weigh more than 12 tonnes and up, the effective, mandatory  commencement date will be three years on from the rule going into effect.