A cyclist was taken to hospital after colliding with a bus in Saltersgate, Parnwell.
A man said to be in his 50s suffered head injuries following the incident on Saturday night (January 23) with the emergency services called after 10pm.
Cambridgeshire police said officers are investigating.
The East of England Ambulance Service sent an ambulance crew and rapid response vehicle, while Magpas Helimedix Doctor Leigh Bissett and Paramedic Chris Hawkins arrived via the Magpas Rapid Response BMW.
The man was then taken by land ambulance to Peterborough City Hospital and was said to be in a stable condition with his injuries not thought to be serious.
Andy Campbell, managing director of Stagecoach East, said: “Just before midnight on Saturday, in dark and wet conditions, one of our buses was involved in an incident with a cyclist at a T-junction on Saltersgate, Parnwell; estimates suggest that the bus was travelling at three to five mph.
“Paramedics attended the scene to treat the cyclist. We are continuing to investigate the events leading up to the incident.”