TULSA COUNTY, Oklahoma - Emergency crews responded to an injury wreck that injured four people on northbound Highway 169 near 36th Street North Sunday afternoon.

Two vehicles, a Chevrolet Malibu and GMC Sierra, collided just after noon. The truck rear-ended the Malibu at a high rate of speed, according to witness descriptions.

Tulsa police confirm that witnesses report the sedan had its emergency flashers on and was trying to move to the side of the road when it was hit from behind.

Four people have been transported from the scene in critical condition including a toddler, according to Kelli Bruer of EMSA. 

EMSA says one vehicle had two adults -- a man and woman -- and the child. She said the boy is about 12 to 18 months old. There was one adult male in the other vehicle.

Traffic was down to one lane for well over an hour as crews cleared the scene. Tulsa police are investigating the injury crash. EMSA said all four involved were taken to a hospital in critical condition, but police said the occupants of the silver car have been downgraded to serious condition.

Seven months ago another car was rear-ended on the same busy corridor between Tulsa and Owasso. Owasso police said a distracted driver caused that crash, which killed an 8-year-old girl.