The A308 is a road in England in two parts. The first part runs from Central London to Putney Bridge. The second part runs from just beyond Putney Heath to Bisham, Berkshire. It traces four, roughly straight lines, to stay no more than 3 miles (4.8 km) from the Thames. It is a dual carriageway where it is furthest from that river, in Spelthorne, Surrey and forms one of the motorway spurs to the large town of Maidenhead. Other key settlements served are Fulham, Kingston (London), Staines upon Thames, Windsor and a minor approach to Marlow