A new study shows drivers are putting themselves at risk from preventable road accidents. 

In a survey of over 1,500 British motorists by sat nav firm TomTom, 44% say they’ve had to brake sharply because of a sudden traffic jam ahead. 

Nearly one in four (22%) claim the car behind has driven into the back of their vehicle when they’ve had to brake suddenly because of traffic.

With slamming on the brakes causing 7% of road accidents in the UK, it is estimated that driving too close to the car in front costs the economy just over £1 billion a year.

Whilst 58% of British drivers claim they always leave the required stopping distance between their car and the one in front, only 44% knew the correct distance at 60 mph (240 feet) – with 56% either under-estimating it or admitting they didn’t know.

Awareness of the stopping distance at 30 mph (75 feet) was even worse, with only 35% getting it right and 65% putting themselves and others at risk by under-estimating it or not knowing.

Despite these findings, a staggering 90% think they have the necessary skills to be able to judge speed and distance accurately whilst driving.

“This new research reveals a serious issue that we aim to address with our technology,” said a TomTom spokesman.  “Our traffic information has become so accurate that we can now pinpoint the precise location of a traffic jam. 

“On our new GO range we have developed a Jam Ahead Warning that shows drivers clearly where a jam starts and crucially alerts them to slow down if they are travelling too fast.”

The average daily total jam length across the UK in September is 248 miles – 35% worse than in the holiday month of August.