It stretches all the way from Perth in the south to Fraserburgh in the north-east, and while it is one of the country’s busiest roads, the A90 is arguably nobody’s favourite.
It doesn’t have the majestic scenery of, say, the A82 Glasgow-Glengarry route – recently named one of the country’s best drives – nor the tourist appeal of the A75 in Dumfrieshire, which is reputed to be Scotland’s most haunted highway.
But for industries and commuters on the east coast, the 135-mile road provides a vital link and is the only direct route between remote parts of the Aberdeenshire corner and the central belt.
The road dates back to the early 1920s, when it only ran from Perth to Edinburgh.
The original route ended at Queensferry, under the Forth Railway Bridge. Motorists had to use a ferry to travel north, which took them across to the then-B902 at North Queensferry.
In those days, commuters going from Perth to Edinburgh used the less watery A9 via Stirling instead, so the A90 wasn’t seen as very important.
However, in 1964, the opening of the Forth Road Bridge changed everything.
The new crossing provided the missing piece in the link between Fraserburgh and Perth.
It had been a trunk road for some time, but was not named the A90 until several years later.
The Perth-Aberdeen section can easily be navigated in less than two hours on a good day.
The dual carriageway section means traffic can zip along relatively swiftly, with not even the inconvenience of having to pass through Dundee causing any major delays (usually).
Once through Aberdeen, the dual carriageway continues to the outskirts of Ellon – only stopping for safety reasons at the roadside village of Foveran.
And then…
Well, then the A90 loses all of its zippiness.
Between Ellon and Fraserburgh, it drops down to single carriageway.
Lengthy tailbacks are a regular sight on this particular stretch, largely due to the vast number of slow-moving HGVs and farming vehicles which use it at all hours.
Although this can be tiresome for commuters heading home from a hard slog in the office, there is a more serious problem.
Road safety campaigners believe upgrading this section to a dual carriageway will save lives by taking away the frustration caused by getting stuck behind large, impassible traffic.
Since 1999, there have been nine fatal accidents on the Peterhead-Ellon stretch alone.
Furthermore, the businesses using the trucks and farm vehicles are always inconvenienced by the single lane route.
Peterhead Port Authority boss, John Wallace, explained that fish lorries have to leave Peterhead at least half an hour earlier than they would if the road was dualled, in order to catch ferries and markets in the south.
Will Clark, chairman of the Scottish Seafood Association, added: “The cost to distribute goods to markets can be the difference in making a profit and or gaining new business.
“In regard to the fishing industry, Scotland is fortunate in having a renowned reputation for supplying the best wild seafood in the world, this is evident in the huge volumes exported every day finding its way to the top restaurants.
“Despite some of the marketing initiatives to promote seafood, these initiatives fail at the first hurdle if the product cannot reach markets in time.”
He added: “Only recently there has been restriction in delivery times into Billingsgate due to congestion in the city.
“A dual carriageway between Peterhead and Aberdeen will achieve huge economic benefits not only financially but in developing new markets and supporting many more employment opportunities to the Buchan region.”
A spokesman for the Peterhead and Fraserburgh Fish Processors Association said: “We would welcome any initiative to improve the road infrastructure in the north-east, specifically the link between Peterhead port, the north-east’s massive economic driver, and the new Aberdeen Western Peripheral Route.”
Five years ago, it emerged that the Scottish Government was in the process of drawing up plans for the dual route, but since then nothing has been heard about the project.
This week, the Press and Journal will look at how the north-east would benefit from a faster moving link between Peterhead and Ellon.
As a campaign launched by councillors – Why Stop at Ellon? – grows on social media, we look at how recent upgrades have shaped the road and how it could be transformed by the much-anticipated Energetica programme.