M90 motorway

M90 motorway
Road of the United Kingdom
Length	30 miles (48.3 km)
Direction	South - North
Start	Inverkeithing near Forth Road Bridge
Primary destinations	None
End	Perth (two ends; one east, one at Broxden Junction)
Construction dates	1964 - 1978
Motorways joined	A823(M) motorway
Euroroute(s)	E 15

The M90 is a motorway in Scotland. It runs from Inverkeithing, at the north end of the Forth Road Bridge, to Perth, passing Dunfermline, Cowdenbeath and Kinross on the way. It is Scotland's – and the United Kingdom's – most northerly motorway, the northernmost point on its spur into the western suburbs of Perth at Broxden.

M90 in Fife

The M90's arguably most substantial engineering feature is the Friarton Bridge in Perth, a tall concrete pillared structure which traverses the River Tay. The bridge carries eastbound traffic from Broxden towards Dundee and along the Firth of Tay.

The road constitutes most of the southerly part of the crucial A90 corridor from Edinburgh, through Perth, Dundee and Aberdeen to Fraserburgh along Scotland's North Sea coast.

The M90 is considered one of the UK's most sub-standard motorways of significant distance. Junctions 1 and 2 share a tiny common sliproad, forcing a conflict between entering and leaving traffic at the junction with the A823(M). It lacks hard shoulders for an 8-mile (13 km) section. In this section there are emergency lay-bys at 1/4-mile (400 m) intervals instead. The M90 also has one of the tightest corners on the UK motorway network, for which some traffic is forced to slow down. The corner cuts through the northern side of the Ochil Hills and has a curve radius of 694.5 m (a minimum of 914 m was standard practice at the time of construction). This corner also corresponds with one of the steepest sections of the motorway, for which north-bound Heavy Goods Vehicles (HGVs) are sign-posted to stay in a low gear and often brake continuously through the turn. South-bound HGVs are normally substantially reduced in speed as they make the incline.

A large part of the northern section of the motorway follows the route of the former railway line linking Perth to Glenfarg, Kinross then onwards to the Forth Bridge. It is not obvious when first driving along the road but close inspection of the 1:25,000 scale Ordnance Survey maps of the route illustrates this^[1][2].

Near to its northern terminus, the motorway splits into two branches. The construction of this three-way interchange required the removal of about 900,000 cubic metres of material, mostly rock. The motorway bends through more than 90 degrees, on a compound curve partly of about 500 m and partly of about 800 m radius. One branch forms part of the western bypass of Perth, and meets the A9 at its end. The gradient is 4.57% uphill and 5.65% downhill on this section. The slip roads forming this branch merge with shared priority to allow HGVs to maintain momentum on the steep upgrade. The other branch heads in a north-easterly direction, flowing into the A90 at its end. The easternmost branch was formerly the M85 motorway, until the A85 was renumbered as A90.

The M90 forms part of the Euroroute E15 which runs from Inverness to Algeciras, but is not signposted within Scotland.

Junctions

See also

• List of motorways in the United Kingdom

References

External links

• CBRD Motorway Database - M90
• The Motorway Archive - M90
• Pathetic Motorways - M90

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