Police investigating a crash on the Monash Freeway on Monday night that left a man critically injured have arrested a 20-year-old man over the incident.
Two cars were seen weaving and changing lanes at about 10:45pm on December 28.
Detectives from the Major Collision Investigation Unit say the vehicles appeared to be racing.
The driver of one car lost control of the vehicle and it crashed into the Springvale Road overpass in Mulgrave and rolled.
The 20-year-old driver suffered life-threatening injuries and was taken to hospital.
His 18-year-old passenger suffered minor injuries.
Police say the other car, believed to be a white sedan, did not stop and left the scene.
The two cars are believed to have been racing for about 6 kilometres prior to the crash.
Investigators this morning arrested a 20-year-old man from Narre Warren, who is being interviewed.
Police also seized a vehicle as part of their investigation.