The chief constable of Thames Valley Police was first to respond to a rush hour collision near Oxford that flipped a car upside down.
Francis Habgood climbed into the overturned car and supported the driver until other emergency services arrived.
Police were called to Middle Street, Islip, near Kidlington, at about 07:50 GMT on Monday.
"It was a single vehicle, damage only collision," a police spokeswoman said.
A tweet by Thames Valley Police said NHS staff and members of the public also stopped to help.
Mr Habgood later tweeted that he was "glad to say that the driver was walking wounded".
"Great working by all the emergency services as always," he added.