What National Highways crash tests found behind every lorry

You are behind a lorry on a fast road and the traffic ahead stops without warning. Your car brakes hard. What happens in the next second has now been put to the test, and the findings are not reassuring.

National Highways has launched a series of crash tests after identifying a serious risk on England’s motorways and major A-roads. The work focused on one specific type of collision, where a smaller vehicle, usually a car, runs into the back of a heavy goods vehicle.

The most common HGV crash is also one of the most harmful

HGVs made up 10% of traffic on England’s motorways and major A-roads in 2024. Yet they were involved in 19% of collisions where people were killed or seriously injured.

Rear-end shunts were the most common type, accounting for 39% of all HGV-related collisions that year. In 2024, 160 collisions involved a smaller vehicle hitting the rear of an HGV. That single type of crash was behind 18% of all serious or fatal HGV-related casualties.

In total there were 1,151 collisions involving one or more HGVs on the strategic road network in 2024, the most recent year for which data is available.

Why the testing started

Roads and Buses Minister Simon Lightwood backed the research.

“Every death on our roads is a tragedy, which is why I am pleased to see National Highways taking the initiative with this vital research,” Simon said.

He linked it to the Government’s Road Safety Strategy, the first in over a decade, and a commitment to cut deaths and serious injuries on the roads by 65% by 2035.

Sheena Hague, Director of Road Safety at National Highways, said collisions where smaller vehicles run into the back of HGVs “can have devastating consequences.” She said the testing helps build a clearer picture of how and why they happen, so practical steps can be taken to prevent them or reduce the impact.

“The freight industry is a vital part of our economy, and we work closely with hauliers and others to help keep all road users safe,” Sheena added.

What the two crash tests found

National Highways worked with Euro NCAP on two sets of tests in February and March this year. The work was carried out alongside Sweden’s national transport authority and Germany’s ADAC, Europe’s largest automobile association, after all three organisations had independently raised similar concerns.

Emergency braking that did not always see the trailer

The first test looked at how well advanced emergency braking systems in cars detect the back of different HGV trailers. These systems monitor the road ahead and apply the brakes automatically if the driver does not react in time.

The results showed variation depending on the trailer design. Older systems did not consistently recognise the rear of a trailer, which meant the emergency braking did not always activate.

The bars meant to stop a car going under

The second test assessed rear underrun protection, the reinforced metal bars fitted low across the back of an HGV to stop a car sliding underneath in a collision. Devices approved to the international UNECE standard were crash-tested and compared with similar tests in the United States.

The testing showed how important that protection is in reducing the severity of a rear-end crash. But some existing designs did not stop the cars going underneath the trailer, and the tests showed severe injury would result for the people inside.