Side-swipe crashes involving foreign HGVs that change lanes and strike a vehicle travelling alongside have been significantly reduced following a trial of new window-mounted lenses.

There was a 59% reduction in such accidents following the distribution of 40,000 Fresnel lenses to left-hand drive trucks entering the UK from the Dover ferry port.

The Highways Agency will now distribute a further 90,000 lenses at major ports in both England and France.

“Many drivers here don’t realise that left-hand drive lorries can’t easily see a car overtaking them on the right, such as on a motorway,” said road safety minister Jim Fitzpatrick.

“This has resulted in more than 400 side-swipe incidents in 2006 alone.

As well as being dangerous these incidents cause delays and congestion.”

All trucks have a blind spot alongside the cab on their passenger side.

This is a particular problem for left-hand drive trucks operating in the UK when they change lanes to overtake.

Fresnel lenses offer those drivers a wider field of vision through the passenger window.

This work sits alongside a wider initiative to improve the safety of overseas vehicles using UK roads.

An extra £2 million of funding has been announced and last summer the Department for Transport confirmed measures to target overseas hauliers who break the law.

They now face on-the-spot penalties and having their vehicles immobilised.