M90 motorway

Key takeaways

M90 motorway belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect M90 motorway to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of M90 motorway from memory before moving on to harder problems.

Reference excerpt

The M90 is a major motorway in Scotland. It runs from Junction 1A of the M9 motorway, south of the Queensferry Crossing, to Perth. It is the northernmost motorway in the United Kingdom. The northern point of the motorway splits into two between the Broxden Roundabout (Leading to Perth and the A9 towards Inverness and Thurso) and the A90 towards Dundee and Aberdeen. The southern point leads into the M9 towards Stirling and the M8 towards Edinburgh and Glasgow. A small part of the M90 (across the Friarton Bridge to the southeast of Perth) was originally numbered as the M85 motorway.

History The first section of the M90 opened in 1964 to coincide with the opening of the Forth Road Bridge and the A823(M) (Junction 2). The section of the M90, between Crossgates and Kelty opened on 1 December 1969. The stretch between Kinross and Milnathort opened in December 1971. Two sections were due to begin construction around 1973 and 1974, however, they were put on hold because of the 1973 oil crisis. The section from Arlary (Junction 8 with A91) to Glenfarg was opened in March 1977. Glenfarg to Bridge of Earn opened on 2 October 1980 connecting with the completed Friarton Bridge (which was originally numbered M85, and opened in 1976) and Perth Bypass to Broxden. The M90 was extended southwards across the Firth of Forth over a new cable-stayed bridge, the Queensferry Crossing, in 2017. A short stretch of the A90 connects the two parts of M90: the short M90 section from the M9 and the much longer M90 section that crosses the Queensferry Crossing and extends to Perth. This short length of the A90 was required at this point as motorway regulations would have prevented certain classes of traffic from using this section of road.

Details

The M90 leaves the east-west M9 near Kirkliston and heads north. The motorway is interrupted by a short stretch of the A90 from where the A90 from Edinburgh joins the M90. The road continues, however the M90 during this stretch is called the A90. Once it reaches the junction to the south of the Queensferry Crossing the A90 becomes the M90 again at that point. The crossing opened as part of the motorway on 30 August 2017; the bridge is configured as a dual two lane carriageway and has a speed limit of 70 mph (110 km/h). Previously, the M90's most substantial engineering feature was 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 A90 corridor from Edinburgh, through Perth, Dundee and Aberdeen to Peterhead along Scotland's North Sea coast. A large part of the northern section of the motorway follows the route of the former main railway line between Perth and Edinburgh via Glenfarg, Kinross and the Forth Bridge, which was closed in 1970 despite this not being recommended by the Beeching report. The Kinross and Milnathort Bypass, the 8-mile (13 km) section of the M90 between Fruix and Arlary, was the first motorway in Scotland to be constructed using concrete pavements that were not reinforced. Both the south- and north-bound carriageways have since been overlaid by tarmac.

Near to its northern terminus, the motorway splits into two branches. The construction of this three-way interchange required the removal of approximately 900,000 cubic metres (32,000,000 cubic feet) of material, which was mostly rock. The motorway bends through in an acute angle, on a compound curve partly of 520.8 m (1,709 ft) and partly of 694.5 m (2,279 ft) in its radius. One branch heads in a north-easterly direction, flowing into the A90 at its end, numbered junction 11 – this branch was formerly the M85 motorway, until the A85 was renumbered as A90. The other branch forms part of the western bypass of Perth, and meets the A9 at its end, numbered junction 12. 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 (also known as Large Good Vehicles or Heavy Goods Vehicles) to maintain momentum on the steep upgrade. The Broxden to Muirmont slip road at the centre of the interchange has a radius of 136.4 m (447 ft 6 in), necessitating maximum superelevation of 7%. The M90 forms part of the Euroroute E15 which runs from Inverness to Algeciras, however this is not signposted within the UK.

Issues The M90 lacks hard shoulders for an 8 mi (13 km) section. In this section there are emergency lay-bys (rest areas) at 1⁄4 mi (400 m) intervals instead. The M90 here has one of the tightest corners on the UK motorway network, for which some traffic can be forced to slow down. The corner cuts through the northern side of the Ochil Hills and has a curve radius of 694.5 m (2,279 ft). A recommended minimum of 914 m (3,000 ft) was standard at the time of construction. This corner also coincides with one of the steepest sections of the motorway, for which north-bound 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.

Junctions

Coordinate list

See also List of motorways in the United Kingdom

References

External links

Scottish Roads Archive - M90

CBRD Motorway Database - M90 The Motorway Archive - M90 Pathetic Motorways - M90 Pathetic Motorways - M85 Diagram of Fife M90 Approaches to Queensferry Crossing

Illustrations

Worked examples

Example 1 — a first encounter with M90 motorway

Start with the simplest possible case. Write down what M90 motorway claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to M90 motorway before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about M90 motorway ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of M90 motorway

In research: M90 motorway appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses M90 motorway in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: M90 motorway is common in secondary-school and first-year university syllabi. It links to neighbouring topics Motorways in Scotland, Transport in Fife, Transport in Perth and Kinross, so understanding it makes those chapters shorter.
In everyday life: Look for M90 motorway outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study M90 motorway in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what M90 motorway means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain M90 motorway out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is M90 motorway in simple terms?

The M90 is a major motorway in Scotland. It runs from Junction 1A of the M9 motorway, south of the Queensferry Crossing, to Perth.

Why does M90 motorway matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study M90 motorway?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on M90 motorway.