On 7 January 2005, the A818 number was recycled to take over the B831 and the southern part of the B832 between the A82 by Loch Lomond and Helensburgh. This was always the preferred route into Helensburgh, avoiding the slow signposted route via the A814 through Dumbarton - and the new A818 has seen much improvement in recent years.
Arden - Helensburgh
Starting at the Arden Roundabout on the A82, we head west along the former route of the B831. After a mile or so, we reach another roundabout at Cross Keys where we meet the B832 which takes us back to Loch Lomond and turn left onto the former route of that road. Straight ahead is the minor road through the valley that has been largely replaced as a through route by the A817 on the hillside above.
Soon the road has crossed the hill, and started to descend into Helensburgh. After crossing the railway line, a side road on the right is signposted to Hill House, one of Charles Rennie Mackintosh's most famous buildings and now owned by the National Trust for Scotland. The road then continues downhill, through the leafy streets of the town, meeting the A814 on West Clyde Street, almost opposite the pier.