One person is dead and a second person still fighting for their lives after a serious crash near Newmarket on Highway 9.
York Regional Police say the crash involved a dump truck and a sedan, just before 2:30 on Tuesday afternoon.
Police couldn't say if this was a head-on crash, or if the vehicles were traveling on different roads. They are hoping witnesses could help answer some of their questions.
They are also checking to see if weather could have played a factor.
"I know there was rain in the area, but I'm not sure if it was raining at that exact time," says Sgt Andy Pattenden.
The driver of the dump truck wasn't hurt.
The ages of the people involved haven't been released.