The two long-serving male officers had stopped a car in Tipton and were speaking to the driver when another car hit them. They were thrown into air by the force of the impact.
One officer in his 40s, who has served with the force for 11 years, was knocked unconscious and sustained a broken leg.
His colleague, also in his 40s and who has served for 13 years suffered serious fractures to both legs.
They are recovering in hospital and are in a stable condition, a statement by the police said.
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She was taken to hospital with a suspected broken shoulder.
"At around 1.30am yesterday the officers, from Old Hill police station, had been speaking to a driver on Dudley Port opposite the railway station when a Blue Volkswagen Golf GTi ploughed into the back of the stopped car," the statement said.
"The force of the crash shunted the stopped Mercedes E350 into the officers before the Golf hit them throwing them into the air," it said.
Chief Inspector Jack Hadley, from West Midlands Police, added: "Despite their serious injuries, this crash could have been much worse for all concerned."
"Paramedics then took over sending three ambulances and three doctors to the scene. I would urge anyone who may have witnessed the incident and has not yet spoken to police to get in touch," he said.
The driver of the car stopped by officers was not seriously injured. Dudley Port was closed for four hours while emergency services responded to the crash.