A REPORT reveals that using a mobile phone behind the wheel is more dangerous than driving under the influence of drink or drugs.
Details of the study emerged in the wake of a court case involving a motorist jailed for a death crash on the A19 near Northallerton, North Yorkshire.
Susan Noble, 29, from Seaham, County Durham, was texting before she ploughed into the back of a stationary car in December 2011.
Alexandru Braninschi, 24, was replacing a punctured tyre when Noble - who had not seen the car - smashed into the back of it at 70mph.
Experts said the Network Rail delivery driver would have had 14 seconds to take evasive action had she been looking at the road.
Prosecutor Paul Newcombe told Teesside Crown Court that she "had her head in her phone" sending two text messages and reading three others.
Afterwards, Sergeant John Lumbard, of North Yorkshire Police, said: "This kind of distraction is actually worse than drink-driving.
"People don't foresee the tragic consequences such an innocuous act can have. Sadly in this case, it did."
The study by the Transport Research Laboratory examined drivers' reaction time and ability to maintain lateral vehicle control.
Reaction times were 35 per cent slower when drivers were writing a text message, compared to those simply watching the road.
Earlier tests showed alcohol consumption to the legal limit caused a 12 per cent reaction time increase and cannabis slowed reaction times by 21 per cent.
The reports says: "When texting, a driver may present a greater accident risk than when at the legal alcohol limit for alcohol consumption or when under the influence of cannabis, reinforcing that drivers should refrain from this dangerous activity."
Judge Peter Bowers jailed Noble for three years after telling her she had created "a substantial risk of danger" by using her handset.
He said: "The use of mobile phones and texting causes a very serious distraction from driving and one which cannot be tolerated."
The court heard that Noble moved to Armthorpe, South Yorkshire, through work and had commuted between there and her family in Seaham.
Her barrister, Rod Hunt, said: "She feels a tremendous amount of guilt."
Sgt Lumbard said: "What this case does show is you can have a decent, law-abiding person who makes such an error of judgement.
"This has resulted in tragic consequences not only for the deceased's family, but also for the defendant's own family and friends."