Twelve people were injured after two separate multi-vehicle pileups at a construction zone on Highway 417 eastbound on Sunday night.

The first happened east of the Greenbank Road exit near Woodroffe Avenue, where construction crews had laid out roadway markers to reduce lanes, at about 10:15 p.m., Ottawa paramedics said in a media release.

A minor crash occurred between a Chevrolet sedan and a GMC pickup truck, and both vehicles pulled onto the right shoulder of the highway, paramedics said. No one was injured at this point.

The driver of the pickup truck was standing outside of his truck when a third vehicle — also a Chevrolet sedan — crashed into the two stopped vehicles.

Construction crews had put up markers to reduce Highway 417's eastbound lanes when the two pileups occurred. (CBC)

Truck driver thrown over concrete barrier

The impact caused extensive damage to the car that was pulled over, which had four people inside, and the driver of the truck standing outside was struck and thrown over a concrete barrier, paramedics said. Debris littered the highway.

Paramedics treated six patients with the help of firefighters. There were four in the first Chevrolet sedan:

A 21-year-old man sitting in a back seat of the badly damaged car was trapped for half an hour while firefighters used the jaws of life to cut him out. He was taken to The Ottawa Hospital's Civic campus trauma unit with serious injuries.

A 24-year-old man was also taken to hospital.

A 23-year-old woman was assessed at the scene for minor injuries.

A 25-year-old woman was assessed at the scene for minor injuries.

The 45-year-old driver of the pickup truck who was struck and thrown over the concrete barrier escaped serious trauma, but he was immobilized by paramedics and taken to hospital for a leg injury.

The 20-year-old driver of the second Chevy sedan that crashed into the two stopped vehicles suffered serious head and chest injuries and was taken to the trauma unit.

22:17 Multiple vehicle collision 417 E at Woodrooffe. Media brief to follow. <a href="https://twitter.com/OPP_ER">@OPP_ER</a> & <a href="https://twitter.com/OttFire">@OttFire</a> on scene. <a href="https://twitter.com/hashtag/ottnews?src=hash">#ottnews</a> <a href="https://t.co/vpzGkG7ZR6">pic.twitter.com/vpzGkG7ZR6</a> —@OttawaParamedic

Car came to complete stop on highway

The second crash happened in the same construction zone just after 11:30 p.m.

A Hyundai Accent came to a complete stop on the highway for an unknown reason, paramedics said, and another vehicle crashed into it at "a great deal of speed."

As a result of that crash, a Toyota Corolla and a Chevrolet car were involved in a minor fender-bender.

The 23-year-old man driving the Accent was extricated by firefighters and taken to hospital in stable condition, paramedics said.

Four people in the Corolla — a 22-year-old woman, a 20-year-old woman, a 30-year-old woman and a 30-year-old man — suffered minor injuries. Two of them were taken to hospital, while the other two were assessed at the scene.

A 39-year-old man in the Chevrolet suffered minor injuries and was assessed at the scene.

Ontario Provincial Police are investigating both crashes.