A9 - M90 - A93

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Where is it?

Junction diagramThe end of the M90 spur (originally the mainline M90) at Perth, where it meets the A9 and the A93 into Perth itself. From the map, it might not look much, but it's one of the busiest roundabouts in Scotland and the centre of the country's road network.

It was nominated by 'Mad Manx'.

What's wrong with it?

Bad Junctions is about poor design, not just places that have run out of capacity. That's why most flat roundabout junctions that have problems don't make it in. Broxden is something quite different.

For one thing, it doesn't seem to be a very well designed roundabout. It's on a steep slope, meaning that heavy goods vehicles tip over here with alarming regularity, causing frequent hold-ups to two of Scotland's key trunk routes. It is statistically the most dangerous roundabout in Scotland because of this.

There's also the small consideration that there is simply no way around it. You can't avoid it, except possibly by going through Perth itself, which is hardly recommended. But there are no easy routes to bypass it in any direction. This is unhelpful when Broxden is the collision point of north-south and east-west journeys across Scotland, and one of the calling points on most journeys between places like Glasgow and Aberdeen or Edinburgh and Inverness.

Why is it wrong?

British road planners (and their whip-cracking political leaders, who write the rule books) like roundabouts. Roundabouts are cheap, they require no maintenance like traffic signals or bridges, they are easy for drivers to use, and they are almost unbelievably versatile. You can take any bizarre road layout and hammer it into a sensible shape with a couple of roundabouts.

It's great to have such a useful tool in your arsenal. The problem is that the roundabout is also the default choice when the traffic flows and turning movements aren't very decisive or you can't make your mind up about who should get priority through the junction. That is what seems to have happened here. You can almost imagine the conversation...

"We've got three high-speed roads meeting here west of Perth. Should we free-flow them together somehow?"

"Which one is the main road?"

"Er... we don't know. It looks like people will be moving around a lot so there won't be a dominant flow through it."

"Oh, that's fine then. Just stick a roundabout in and we'll put the spare cash towards the Christmas party."

What would be better?

Without having access to the traffic flows and a model of the turning movements that are made here, it's hard to say where a flyover or a bypass should go. Do more people go between the A9 to the north and the other arm of the A9, or do most of them actually head for the M90? Without knowing it's hopeless to speculate.

Some quick and effective fixes could be found, however, by some more left-turn lanes to enable, say, northbound A9 traffic to continue non-stop. You could also erect some signs warning lorry drivers that there is a severe risk of tipping over, because the word obviously isn't getting out. Just an idea.

Right to reply

Hate this junction? Or do you think it hasn't had a fair trial? Make yourself heard! Post a comment.

These are the most recent comments on this junction. You can see all comments if you prefer.

November 2015

Chris Walker thinks something isn't right:

The thing that always catches me out about this roundabout is the lane markings on the approach from Stirling. For some reason, there's no right-turn marking at all, only left and straight-on, with both the A93 and M90 junctions being treated as straight-on.

This is doubly-confusing, because you can actually turn right onto the M90 from the left lane, which has a straight-on-and-left arrow painted on it.

December 2014

Steph lived to tell the tale:

We survived it. I must say this was the scariest of all roundabouts we encountered on our holiday. Being from Canada and already out of sorts with see oncoming cars hurtling towards us on what should be the passenger side, we thought we had developed some kind of truce with the excellent traffic circle concept. We were headed for Stirling with the use of the Welcome to Scotland app when we found ourselves at this massive circle: and uprecedented three lanes wide, heavy traffic sailing along at 50 miles/hr, and having no choice but to put the gas pedal to the floorboards to enter the melee, we got in. The phone app seemed to list different road numbers for our exit than what we saw on the signs, and counting the number of roads before we should exit didn't inspire confidence. My poor husband who was stuck with the driving had to go round three times before all occupants of the car collectively agreed on which exit to take. We ended up at Bannockburn. That wasn't so bad. We just took in a little more history before venturing to our intended destination. Like I said, we survived it. It was one of the hallmarks of our adventures in Scotland, but I wouldn't care to repeat it.

February 2012

Matt has the answer:

The most annoying thing about this junction is the lack of left turn lanes. More and more often these days you have to queue for 10 mins to turn left from the M90 spur to A9 south. That's cheap and easy, why hasn't it been done?

For grade separation, remove the A93 from the junction and it's a simple directional-T. I'd like the A9 to be the through route to remove the TOTSO, but it doesn't really matter.

Divert the A93 down the B9112 and build a junction where it already passes underneath the M90 spur.

Too easy?

October 2010

Michael has news:

The local council has granted planning permission to erect a 6m high sculpture on this roundabout, as part of Perth's 800th anniversary celebrations. The sculpture will stand on an 8m plinth, and will depict a grouse taking flight - no doubt scared by all the traffic! I wonder how this will affect any proposed improvements?

July 2010

Kevin knows no fear:

I am a native Glaswegian who now lives in Tayside - therefore I've been immunized against Broxden Junction by years on Scotland's road to hell - the M8. Yes - it's a game of Russian Roulette sometimes at rush hour trying to get onto the southbound A9 from Perth but it's easy enough once you have the knack. But look at the almost perfect alignment between the A9 Northbound and the M90 - why not sink the road down (like the Gyle interchange on the A720 Edinburgh City Bypass), and then you can freeflow from the M90 to A9, and have a flyover or something for the A9 south to Stirling? Maybe that was the original intention???