The road was closed for three-and-a-half hours to allow officers to carry out investigations at the scene. Officers would like to hear from anyone who witnessed the collision or saw the motorcyclist prior to it.
Anyone with any information should contact Totton Roads Policing Unit, quoting Operation Froggen, on 101, or the Crimestoppers charity anonymously on 101.
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Police body cam footage captured the incident in Brighton in June 2013.