Emergency crews in Abbotsford responded to a serious collision involving two pedestrians, an adult and a child.

Debbie Hawryliw works nearby and was jolted from her desk in the moments after the crash. She said she heard the tires screeching, a thud and screams.

"Horrific sounding," she said. "It was just a shock from the bottom of your spine to the top of your head."

Abbotsford police said it happened at the intersection of Montrose and Essendene avenues on Sunday around shortly after 10 a.m.

Hawryliw said a couple of bystanders with first aid kits rushed to help stabilize the man while they waited for the ambulance to arrive. She said luckily, the boy was not seriously hurt.

Police said the man was taken to hospital with serious injuries.

Hawryliw said she saw an elderly woman was behind the wheel.

The intersection was closed for several hours while police investigated.

"The reason why the road is closed is so that our reconstructionists, with the evidence that is there, can do a proper investigation. Due to the fact that it did involve pedestrians, that is why our analysts are there out of caution," said Sgt. Judy Bird.

The road was reopened in the afternoon.