Glynn Turner, 47, from Ipswich, was riding his motorcycle south on the A12 on the evening of 7 June 2010 when he collided with the traffic signs at a road closure at the junction with the B1121, near Benhall, Saxmundham.
Turner, a father of three, sustained multiple injuries. He is now unable to move any part of his body, is unable to communicate, and needs 24-hour residential care. His family have been told there is no prospect of a recovery.
An HSE investigation found that the first indication of roadworks was less than 200 metres before the road closure on the 50 mph stretch of the A12.
Ipswich Crown Court heard that the company was responsible for placing a series of road signs warning of the closure and directing traffic along a diversion route.
The ‘roadworks ahead’ signs should have been erected at intervals of around 800, 400 and 200 metres in advance of the closure, and information signs alerting road users should have also been placed at up to one kilometre in advance.
HSE found that at the time, the first indication of the road closure was just 175 metres before it happened where a large yellow information board had been placed.
But, as the speed limit on that stretch of road was 50mph, this left little time for traffic to slow down and avoid a collision.
Carillion AM Government Ltd, of Birch Street, Wolverhampton, pleaded guilty to a safety breach and was fined a total of £180,000 and ordered to pay £28,551 in costs.
Speaking after the hearing, HSE Inspector Sandy Carmichael said: “This was a tragic incident that was utterly life-changing, not just for Mr Turner but also for his wife and family.
“He was an experienced driver who travelled that route regularly between his home in Ipswich and his work in Sizewell.
“Had Carillion complied with the industry’s code of practice and correctly placed temporary warning signs to alert motorists in good time to the roadworks, this dreadful incident could have been avoided.
“Sadly, as a result of the company’s failure to take simple safety measures, road users were put at serious risk and Mr Turner was so badly injured that he has been left completely paralysed.
“Roadworks provide increased risk in what is already a very hazardous environment. Anyone doing work on our roads must take great care to warn road users in good time what to expect on the road ahead.”