The victim, a 52-year-old local woman, was found beside a Vespa scooter on the A259 westbound, prior to the Body Shop Roundabout, around 7.09pm on Thursday 28 October.
She has been taken to hospital with head injuries.
A section of the road has been closed in both directions while emergency services respond to the scene.
Police are urging anyone who saw what happened, or anyone with any relevant dash cam footage, to email email@example.com quoting Operation Marshal.
In the meantime, an investigation is ongoing to establish the cause of the woman’s injuries, and to determine if any other vehicles were involved.