Bethany Jones, 18, died and others in the party - including her mother and sister, and the bride-to-be - were seriously injured in the crash on the M62 near Pontefract, West Yorkshire.
The bus they were travelling in had come to a complete stop on the motorway after its clutch failed, and a lorry ploughed into the rear.
James Joseph Johnson, who had suffered two strokes and should not have been driving, was jailed for six years and eight months at Leeds Crown Court in November last year.
The bus driver previously admitted causing Bethany’s death by dangerous driving.
The 65-year-old, of Whytecote Road, Wyke, Bradford, today challenged his sentence at London’s Criminal Appeal Court, with his lawyers arguing it was ‘too long’.
But his complaints were thrown out by three senior judges who ruled his punishment was ‘justified’ in light of his ‘completely thoughtless behaviour’ and its devastating results.
The court heard Bethany, of South Elmsall, near Wakefield, and the other 19 members of the hen party were on their way to Liverpool to celebrate when the crash happened at about 11.30am on 26 April 2013.
Shortly after they set off, some of the women complained they could smell burning, and Johnson pulled the 24-seater coach over.
But, after making a ‘cursory examination’ of the vehicle, he carried on driving.
As he drove along the M62, the bus began to lose power and slowed to as little as five-miles-an-hour.
Several other road users beeped to warn him, but he ignored them and ploughed on - passing a junction without turning off and failing to move onto the hard shoulder or to put his hazard lights on.
Just 100 metres past the junction, a lorry ploughed into the back of the coach, propelling it several metres.
The lorry driver was cleared of any wrongdoing after a trial.
Bethany, a trainee nurse, was pronounced dead at the scene, while her mother, Diane, and sister, Amy, were severely injured.
Other women in the bus were also seriously injured and the court heard many would never recover fully.
Medical experts concluded that Johnson should not have been driving at the time of the crash and said he had poor memory and concentration, following two strokes in 2008 and 2011.
The last stroke happened while he was driving 16 nurses in a minibus on the motorway in 2011, and a crash was narrowly avoided after one of the nurses managed to stop the bus.
Following that incident, he was off work for six months but then returned to driving.
Jailing him, Judge Guy Kearl QC said Johnson had shown a ‘flagrant disregard’ for the rules of the road, and must have known - having been a bus driver for 37 years - that his medical condition impaired his ability to drive.
On appeal, his barrister, Samuel Green QC, argued the judge didn’t take enough account of Johnson’s medical condition, saying this ‘reduced his moral culpability’ because he had cognitive disabilities as a result.
But, dismissing the appeal, Mr Justice Cranston said the judge’s sentencing remarks were ‘careful and thorough’ and took account of all the factors.
Sitting with Lady Justice Rafferty and Judge Deborah Taylor QC, he added: “In ordinary terms, this was completely thoughtless behaviour, with appalling consequences for so many other lives.
“In our view, the sentence cannot be regarded as manifestly excessive or wrong in principle.”