Police said the crash happened at Cleland just before 3.30pm on Monday.

Emergency services freed the 24-year-old man from a blue Toyota Corolla and he was taken to the Royal Adelaide Hospital in critical condition, but he died  overnight.

Mount Lofty Summit Road was closed for several hours while Major Crash officers examined the scene but was reopened about 7pm.

Investigations into the crash are continuing. The state road toll is now 84 compared with 55 at the same time last year.