On reaching the boundary between Glasgow and West Dunbartonshire the route once again becomes a dual carriageway. In 2022, a major junction will be constructed here to provide access to the Yoker-Renfrew swing bridge across the River Clyde.

 

The road continues westward passing Clydebank and Yoker, becoming single carriageway once again. At Old Kilpatrick it passes beneath the Erskine Bridge and immediately to the north of the Forth and Clyde Canal. To the west of Bowling, a short stretch of the A814 multiplexes with the A82. The two separate at its junction with Glasgow Road, signposted in paint on a sandstone wall.

​

After passing through the centre of Dumbarton the road crosses the River Leven. From here it becomes rural in character, opening up stunning views of the Firth of Clyde and the towns of Port Glasgow and Greenock on its southern shore. On reaching Helensburgh, the road becomes urban once more, still with stunning views of the Clyde.

​

On leaving Helesnburgh the road turns north westwards, running along the shore of the Gare Loch. This section, upgraded by the M.O.D in the 1970s and 80s, passes the main gates of the Faslane Naval Base, home base of the UK's nuclear submarines. A "No Stopping" order is in place along much of this stretch which also features a section of carriageway constructed to 2+1 standards. The upgraded road, which continues past the A817 to the B872, acts as a bypass of Garelochead. Its modern design features are easily recognised.

​

The final section of A814 is mostly unimproved and narrow with poor horizontal and vertical alignment. There is no white lining in the centre of the carriageway, which is barely wide enough for two cars to pass. Skirting along the east shore of Loch Long, its views of the surrounding landscape are particularly impressive. It continues northwards, meeting the A83 in the centre of Arrochar.