The 16-year-old girl and 19-year-old man suffered fatal injuries when a blue Nissan Skyline hit a number of onlookers who had gathered on the A457 Birmingham Road and Oldbury Road in Oldbury at around 11.30pm on Sunday.
West Midlands Police has said officers are now investigating the crash near the junction with Crystal Drive, and have arrested a 54-year-old man on suspicion of causing death by dangerous driving. He remains in custody.
A man and a woman, both in their 20s, also suffered serious injuries. They have been taken to hospital where their condition has been described as life-threatening.
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 and photos or video from the incident on social media.
“I would ask people not to share videos or photos on social media. If you have anything that could help with our investigation, then please get in touch," he continued.
"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.
"I want to thank everyone who has provided a statement so far, and ask anyone else with dashcam footage or any other witnesses to contact us."
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 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.”
The scene at Oldbury Road and Birmingham Road has been re-opened after being closed for several hours.
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.