One crew from Hampshire Fire Service attended the incident in Emsworth Common Road at about 8.25am. It said only one vehicle was involved and there was one casualty suffering back and neck pain.
The casualty was treated by ambulance crews.
West Sussex Fire and Rescue Service said: "RTC involving one vehicle on Emsworth Common Road this morning near Westbourne at 8.25am. Crew from @Emsworth26 were first on the scene, and worked with @SECAmbulance @sussex_police"
Emsworth Fire Station tweeted: "Assisting @WestSussexFire this morning. Take it easy on the wet roads. #RoadSafety #SlowDown #BetterLateThanNever #Emsworth #Chichester #RTC"