A 50-year-old woman from Doncaster was airlifted to QMC Nottingham following a collision on the A1 at the Marston junction yesterday evening.
It happened at about 6pm when her Renault Clio, which was crossing from the northbound carriageway, collided with a Mercedes Sprinter van driven by a 65-year-old from Hertfordshire.
A brown Staffy-cross which was travelling in the Clio broke free and was last seen heading northbound towards Foston. It is a rescue dog and is microchipped.
Anyone with information about the dog is asked to ring police on 101 quoting incident 330 of 29/9.