Norman Yan and his wife, Sandy Yudin, from Bracebridge, were on a shuttle bound for Pearson airport with eight passengers.

“Our driver was amazing,” Yan said. “It was his first accident in 18 years, and he wasn’t going that quickly.”

The shuttle slid into a truck before being hit from behind.

“It was scary,” Yudin said.

Only one passenger was injured in the collision.

“It was chaotic, but they knew what they were doing,” Yan said.

The couple was on their way for a 3 p.m. flight to Calgary to visit a 93-year-old aunt.

Ten or 12 people were reportedly transferred to Royal Victoria Regional Health Centre by a Barrie Transit bus. The nature and seriousness of their injuries is not known at this point.

In addition, about 500 litres of diesel fuel leaked onto the highway.

The collision scene is close to the last winter pileup in 2014.

Meanwhile, the OPP is advising motorists to avoid driving on all Simcoe County roads until further notice, as numerous multi-vehicle collisions have been reported.

Sideroad 5 is being used as an alternate route to Highway 400, but the volume of diverted traffic is causing a significant backup.

Tow trucks are taking affected vehicles to Georgian Downs, which is where stranded motorists are also being transported.

Emily Pelka, a photographer from Newmarket was on her way to a photoshoot after leaving her boyfriend’s house in Barrie.

“I was driving about 80 km/h and the transport ahead of me slammed on their brakes,” Pelka said. Pelka said her car sustained no damage, stopping about three feet from the transport in front of her.

Stuck in the ensuing gridlock for about two and a half hours, a city bus took Pelka and other stranded motorists to Georgian Downs.

“My car didn’t get hit,” Pelka said. “I might get my car tonight or tomorrow.”

Simcoe.com will have more details as they become available.