Officers believe there would have been a number of witnesses to the collision as it was a busy part of the day and are appealing for anyone with any information to get in touch.
Witnesses are asked to call officers at the Kent Police roads policing unit by calling 01622 798571, quoting incident reference 04-0559.
More top news
Saturday evening's weather update for the east
Saturday evening's weather update for the west
A man from Eastbourne who was stabbed by the Westminster attacked has told ITV Meridian he should have been jailed in 2003.