The incident - highlighted on Twitter by Traffic Scotland - took place at J13 at Abington, South Lanarkshire.
It later emerged that a sheepdog called Don, owned by farmer Tom Hamilton, had leaned on the controls of his utility vehicle, taking it on to the road.
Police and Mr Hamilton later recovered Don, who was unhurt, and the vehicle, from the central reservation.
Mr Hamilton told BBC Scotland that he was out on his off road pick up checking lambs in a field above the M74 near Abington.

http://www.bbc.co.uk/news/uk-scotland-g ... t-32411621