M85 Friarton Bridge

Where is it?

South of Perth. It's now part of the M90.

Can you show me that?


Ah, right - another lost motorway.

Yes, that's right.

So, what's the story here?

OK, Scottish motorways are numbered differently to those elsewhere in the UK.


Well, they are named after the A route that they follow - which explains why there's no M7.

That's all very well, but what has that got to do with the M85?

It was renumbered simply because the "90" route took over the "85" route north of Perth. This meant that the M85 had to go, and the M90 took over the M85 route.

That seems a bit daft. So, what happened to the old bit of the M90?

Nothing much - it's still part of the M90.


Yes, that's right. There are two equal M90s south of Perth - one goes to the west of the city and one to the east.

Isn't that rather confusing?

Yes, it is.

As you head north, neither of the options are signed "M90", but "(A9)" and "(A90)".

That's mad.

I couldn't agree more!

Have you got a map showing the M85?

Of course! Here's one showing the motorway under construction that has something odd about it. And here's one once it opened.

Can I comment on this motorway?

Of course! Contact me and I'll put them here!

Have any other visitors commented?

Gerry McKenna likes the bridge:

Quite a spectacular view over Perth and surrounding countryside from this motorway as it soars across the Tay valley on the Friarton Bridge.

I just wonder if environmental concerns would have let them build the same thing today!

Niall Wallace disagrees with me:

The Broxden roundabout looks affy empty back then.

Never thought of the numbering as confusing though, as you cross the Friarton bridge from Dundee you have a choice, take the slip road up the hill and over to get to the A9 or keep on the main carriageway to go towards Edinburgh.

So what is confusing is that you left the A85 and went onto the M85 to cross the Friarton bridge, which then became the M90 without changing road, but to head in the other direction on the M90 you had to turn off.

Now that is confusing!!!

Stuart Mitchell points something out:

Interesting about why the M85 was re-named M90 to follow the road. However.. they could've kept it!

If you look at a map of Dundee, you'll see that the link from the new A90 to Dundee centre is indeed the A85. So the A90 from Perth to Dundee is in fact multiplexed with the A85.

.. which also means that the A9 west of Perth could be considered multiplexed as A85 if Crieff Road was re-numbered.. so that the section of M90 to the West of Perth could become M85 - finally re-instating the motorway!

David Gartside has an intimate relationship with the M85 [September 07]:

M85 Friarton Bridge   

Would they have built it today?

Who knows, but you'll see that it has many similarities with the Avonmouth Bridge on the M5, having been designed by the same consulting engineers - Freeman Fox & Partners.

Employed by them as a young graduate engineer in the early Seventies, I worked on the erection stresses for an alternative design - a cable-stayed concrete box girder.

Let's just say that the cleaner design got built !

Given that the computing power available to us was only slightly greater than a pocket calculator, I never had total confidence in my calculations, so I wasn't too upset when we were stood down from the project.

The finished job is still great fun to drive over. Super view from the top of Kinoull Hill - well worth the short walk.


Friarton Bridge




2 miles

3 km





Map Links:

Might Have Been Map

Present Day Map