 Although comparatively short it is a busy road connecting a number of other A roads with the M25 motorway.The A243 starts at the Knoll roundabout in Leatherhead with the A24, and the B2122 (to the town centre).It then runs for about half a mile before coming to a large roundabout, that is half of Junction 9 of the M25 motorway (to join its clockwise side).