At around 7am, officers were called to reports of a collision between a car and a motorbike on the southbound entry slip road at junction 11a.
The car, described as a dark grey hatchback, had left the scene before emergency services arrived.
The motorcyclist was taken to hospital with minor injuries.
PC Elliot Wright, from the Bedfordshire, Cambridgeshire and Hertfordshire Road Policing Unit, said: “We are working to establish the circumstances of this collision and are looking to speak to anyone who may have witnessed it. Failing to stop at the scene is an offence, which we take very seriously.
“If you have information or any dashcam footage from around the time of the incident, please get in touch.”
You can contact police online or by calling 101 quoting reference 49 of 30 January.