The serious collision happened on the A286 Stockbridge Road in Chichester at around 9.25pm, Wednesday, November 22.
A Sussex Police spokesman said: “A grey Suzuki Grand Vitara, travelling north, collided with a wall and two parked cars, and overturned. No other vehicles were involved.
“The driver, a local woman in her 70s, and her passenger, a local woman in her 60s, were sadly pronounced dead at the scene.”
The road was closed between the A27 Stockbridge Roundabout and St George’s Road until about 2.40am on Thursday, November 23, while emergency services were in attendance, the spokesman added.
Police are appealing for anyone who saw what happened to report it online at https://www.sussex.police.uk/rtcappealresponse or phone 101, quoting Operation Penmark.