Jean-Sebastien Gauthier said there was a horrible inevitability to the accident that unfolded before his eyes.

Gauthier was turning off 29th Street West onto Idylwyld Drive around 8:30 a.m. CST when he watched a City of Saskatoon patching truck turning onto 29th Street across the grassy median.

A cyclist was in the right-hand lane. Gauthier watched the truck's boom extension knock the rider off his bike as both turned right.

Jean-Sebastien Gauthier (Dan Zakreski/CBC) "The painting thing was scooping him around. It knocked him off his bike, he fell and rolled under the front wheels and was pinned at about the midsection under the rear wheels," Gauthier told CBC News.

"It was like watching the inevitable roll out."

A Saskatoon cyclist is in hospital after being struck and pinned by a City of Saskatoon patching truck this morning. 0:29 Gauthier began honking and screaming at the driver, who he said likely didn't even know that he'd hit someone. He managed to get him to move the truck off the cyclist.

"Once he rolled under the front wheel I thought, "Oh God, I hope I can make him stop." And he did, and the other guy was pinned, about half pinned, his hips were under it."

At that point, a volunteer firefighter arrived on scene. Gauthier said he showed remarkable poise, helping the cyclist and getting his name and birth date as Gauthier called 911.

The cyclist was taken to hospital with unknown injuries.

The incident is still under investigation.