The incident happened on the northbound carriageway of the M9 between junctions one and two in West Lothian, around 5.50pm on Friday, September 3.
The bicycle, which had come free from an unknown vehicle travelling on the opposite side of the carriageway, hit the windscreen of a white Ford Focus.
The 60-year-old female driver brought her car to a stop on the hard shoulder and was then taken to St John’s Hospital in Livingston with minor injuries.
The bicycle is described as a Kona Kula 2-9 pedal cycle with a 16 inch light blue and white coloured frame.
Sergeant Jennifer Forbes, of Police Scotland's Road Policing Unit, said: “The consequences of this incident could have been far more severe and it is only through pure luck that nobody was more seriously injured or worse.
“It should stand as a stark reminder of the importance of making sure that any load being carried out on your vehicle is properly and thoroughly secured.
“We are carrying out enquiries to identify the vehicle which had been carrying the bicycle and I would urge anyone who can help to come forward.
“We would be keen to speak to anyone who may have witnessed the incident. If you were on the road late on Friday afternoon and may have dashcam footage which could help our investigation then please get in touch."
If you have any information to share you should contact Police Scotland on 101 quoting incident number 2590 of September 3.