Nicholas Raynham, 44, from Stowmarket, Suffolk, was jailed for 16 months for dangerous driving on the A38 in Staffordshire in 2009.

Dawn Hill, 51, from Tamworth, had to have a metal plate inserted into her skull after the car she was in was hit in a pile-up.

The Court of Appeal reduced the sentence to 12 months.

Raynham was jailed at Stafford Crown Court in December 2010 after pleading guilty to dangerous driving.

'Life-changing' injuries

Several people were injured in the crash, the court was told.

Judge David Radford, sitting with Mr Justice Roderick Evans, told the London court how Raynham, of Woolmers Close, was unable to explain how he had caused the crash.

Traffic had slowed in front of him south of Burton-on-Trent, but he failed to brake in time and slammed into the back of another car, sparking a multi-vehicle pile-up.

Mrs Hill, who was on her way to hospital for chemotherapy treatment, suffered the worst injuries when her husband's car was shunted underneath the trailer of another lorry.

She suffered "life-changing" injuries, Judge Radford said, having to have a metal plate inserted in her skull.

Raynham, who suffered rib injuries himself, could not remember much of the crash, but accepted that he must have lost concentration at the wheel.

His lawyers argued that the 16-month term, close to the two-year maximum for the offence, was much too severe.

"The offence involved the serious failure by the driver of a heavy goods vehicle to pay attention...until too late to avoid multiple collisions," said Judge Radford.

But despite the seriousness of the offence and its effect, the jail term was too long, the judge concluded.