A 16-year-old girl and 19-year-old man died after a blue Nissan Skyline hit a crowd of onlookers on the A457 Birmingham Road and Oldbury Road at around 11.30pm on Sunday.
Two more people - a man and a woman both in their 20s - are fighting for their lives in hospital.
The road was closed for several hours but had reopened by mid-morning on Monday.
Photos from the scene of the crash, near the junction with Crystal Drive, show a partially damaged wall running alongside the main road, as well as debris left by the blue Nissan.
West Midlands Police is now investigating the crash, and arrested a 54-year-old man on suspicion of causing death by dangerous driving. He remains in custody.
Detective Sergeant Paul Hughes, from the force's Serious Collision Investigation Unit, said: "This is a tragic incident and our thoughts remain with all the families affected. We have specialist family liaison officers supporting them at this terrible time.
"We know that there were lots of people who had gathered in the area at the time of the collision and would have witnessed what happened. I would urge those people to get in touch if they haven’t already done so."
He also urged people not to share images or video of the incident on social media, adding: "This is very distressing for the families affected and it’s not appropriate for them to see things that could upset them on social media."
West Midlands Ambulance Service sent three ambulances, two paramedic officers, a MERIT trauma doctor and critical care paramedic, and a BASICS emergency doctor to the scene where they found five patients. A spokeswoman said crews arrived to find five patients.
“The first and second were a man and a teenage girl, who were pedestrians, in a critical condition," the spokeswoman said.
“Unfortunately, despite the best efforts of ambulance staff it became clear that nothing more could be done to save them and they were confirmed deceased at the scene.
“Two more pedestrians, a woman and a man had sustained life-threatening injuries.
“They received advanced trauma care from ambulance staff at the scene and en route to Queen Elizabeth Hospital.
“The fifth, the driver of the car was assessed by ambulance staff at the scene. He had sustained non-life threatening injuries and was discharged at the scene.”
Please email FL_COLLISION_INVEST@westmidlands.police.uk, message Live Chat at west-midlands.police.uk between 8am and midnight, or call 101. Quote log number 3732 of 20 November.