West Street Interchange

The 'ski jumps' at the south east side of the Kingston Bridge, pictured in 2010

West Street Interchange is junction 20 of the M8, connecting it to the A8, via unclassified surface streets. The junction was planned to be the southwestern corner of the Glasgow Inner Ring Road motorway box around the city centre, but when the southern part of this route was finally built nearly half a century later, it took a very different form. This has left a pair of unused 'ski jumps' between the two sliproads, which are regularly used as parking for plant and recovery vehicles during maintenance works on the M8. With the original plans unfulfilled, the junction is simply a pair of sliproads which turn east at the south end of the Kingston Bridge over the Clyde. The offslip has two lanes dedicated to it across the bridge, which curve round and drop to the ground to meet West Street at a signalised fork. Here, the left lane is a dedicated left turn round on to Wallace Street, while the right hand lane allows traffic to turn right or continue ahead. All of these options provide a connection to the A8, which uses the next two one way streets a block further to the north.

The onslip is somewhat different, in that it begins at a signalised crossroads a little further south on West Street and heads west, curving round to the north as it crosses over the M8 mainline. It too has two dedicated lanes across the Kingston Bridge, but they are entirely segregated, and while under motorway restrictions, at no point can traffic cross over on to the mainline. Instead this outer carriageway splits at the north end of the bridge, the left lane curving left onto the A814, Clydeside Expressway, while the righthand lane splits again. The lefthand lane drops down onto the A804, which runs partially under the motorway here, while the right hand lane picks up traffic from the M8 mainline, and then climbs round to the right, over the motorway and onto Bothwell Street, which heads into the city centre.

The original plan was for the unused 'ski jumps' to form the southern side of Glasgow's motorway box, ultimately built as the M74 a little further south. As such, there is no direct connection from the M8 across Kingston Bridge to the M74, and vice versa. However, when the M74 was finally built, it was provided with a pair of sliproads at J1, which were designed in such a way that traffic only has to make left turns to transfer from one motorway to the other. Traffic from the western arm of the M8 can also access this area via J21 a short distance to the west.

Routes

Route	To	Notes
M8	(M8 East) Edinburgh, Stirling, Dumbarton (A814)	sliproad. For M8 East Edinburgh, Stirling & Carlisle follow Charing Cross
M8	(M8 West) Greenock, Gl'w Airport, Paisley	no direct connection from J20
	(M8 West) Greenock, Gl'w Airport, Paisley	Gloucester Street
	City Centre, Kilmarnock (A730), (A77), Diverted traffic (M8 EAST)	West Street northwards
	Scotland Street, School Museum	West Street southwards
	Diversion Greenock (M8)	Wallace Street westwards
	Eglington Toll, Pollockshields, Scotland Street, School Museum	Wallace Street eastwards