The LARGEST ROUNDABOUT on the M4 Motorway & A470 - What Was There Before?

#infrastructure #driving #wales
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In this video, we take a look at the largest, I think, roundabout in the country which sits on the M4 motorway. Not only that, we'll explore the left overs and abandoned road infrastructure that pre dates this massive roundabout and motorway junction.

[@aston-s]

Ive just spent 2 minutes watch someone go round a roundabout. Do I regret it? No.

[@orbtastic]

There was an old video, back in the late 80s or early 90s that was someone doing a lap of the M25. I think it was called Orbital. Roughly the same time as the M25 raves and those "chill out" videos you could get with fractals and computer generated images. When I say video, I mean physical VHS tape. It was required viewing at 3am. Still got my old Xmix videos somewhere.

[@toadcoma3114]

Great traffic light timing as well

[@harveyshaw1466]

Thanks to this comment, and my subsequent search on KZbin to see if this video had been digitised, or someone else doing something similar​, and found that our man John, had done a 1k miles on one tank around the m25 video. Ironically around 25 mins long 😁@@orbtastic

[@DW-indeed]

​@@orbtastic Well, I quite like Orbital (the group) and consider In Sides one of my all time favourite albums. Today I learned that they're named after the M25 and nothing to do with space! 😂

[@MichaelAbbott-sl2di]

Ah, but did you hit the special.button to say you liked it? It's there for that specific purpose 😂

[@juststeve5542]

Look at all those green lights on your lap! The force is strong in this one!

[@georgeprout42]

I used to listen to local radio before it became part of Heart and lost its soul. It was always funny to hear the morning traffic report "there are traffic light failures on Castle Hill roundabout and as a result there are none of the usual delays in any direction".

[@juststeve5542]

@@georgeprout42 I remember the same with my local High Street! Traffic never flowed freer than when the lights broke!

[@mikeuk666]

Only 6 lights

[@tweaker1968]

I bet the guy behind you was thinking "I'll follow the guy in the Saab, he looks like he knows where he's going"

[@fraserdavidson278]

The Gran Turismo music was the perfect accompaniment to the end there 😂

[@-Lucky-Six-]

i thought more like you hit no1 on the leaderboard on Sega OutRun

[@pluxauag7555]

I thought it was Out Run, not the magical sound shower track.

[@sputumtube]

I thought it was a Greenslade track I'd not heard before..

[@thefunkygib]

I was thinking more Outrun, or Ridge Racer.

[@liambethell2584]

I don’t know whether it makes me sad or just really boring when my dinner entertainment is just watching a guy drive round a roundabout.

[@TheCatBilbo]

All of these, but that's okay. To some people, this is very interesting. Learning something new is key.

[@Original50]

'Good luck with that!' Is SO British. True scorn delivered as a blessing. 😅

[@jonc4403]

Not quite as literally a blessing as the American South's "bless your heart".

[@Original50]

@@jonc4403 It's up there though 😄

[@patmatten]

I am utterly addicted to your content, your sense humour and your continuing wit! Nobody else could do what you do and deliver this content in such a downright bloody brilliant way! Keep it up mate, you make the world a better place. Thank you.

[@chopper602]

Having visited for work, the Traffic Wales control centre in the middle of roundabout, it's worth noting that it has it's own set of traffic lights, stopping the traffic on the roundabout to allow you to get on - nice!

[@orwellboy1958]

It's ok in a roundabout sort of way................ I'll get my coat!

[@David_Crayford]

You will need it. It's summer in the UK.

[@TomTomicMic]

....or is that a jacket!?!

[@chrismarsh8162]

The music sounds like a 70's adult entertainment film, so I'm told.

[@saltbjorn]

So you’re told.

[@TheCatBilbo]

Bum-chikka-wow-wow....erm, I've been told.

[@MrAlwaysBlue]

Those VHS 20th hand videos were so stretched and grainy. So I'm told.

[@alexhajnal107]

@@MrAlwaysBlue And a few specific segments were much grainier than others. So I'm told.

[@MrAlwaysBlue]

@@alexhajnal107 😂

[@ljw5768]

As a kid lived near Pontypridd alongside the Glamorganshire canal, which became the route of the proposed new A470. For a year in around 1973 the A470 was almost finished but remained unopened. It was the best cycle track in the world for a 14 year old.

[@simonjones1342]

One junction south on the A470 North Road is the lovely Gabalfa Interchange with the A48 Eastern/Western Avenue. An underpass, a flyover and a roundabout. A three layer cake of motoring madness, not forgetting the A469 and the entrance to University Hospital of Wales, which it looks like the planners nearly did. Do have a look if you're passing. You'd be mad not to.

[@slughead]

My first driving lesson took me around the Gabalfa Interchange - I was terrified.

[@AintBigAintClever]

Not to mention the footpaths that go over the underpass but under the roundabout and the exits off the sliproads that aren't at the end of the sliproads.

[@jonesyboy69]

My wife takes a massive detour through Whitchurch,Llandaff North and Llandaff to avoid Gabalfa lol

[@Devilstrill]

I use it very regularly, and like to refer to it as "the Gabalfabout". You're right that it is a very interesting junction, but the roundabout is a right pain to get into from at least 4 of the 5 points of entry.

[@Loadarine]

A469 that connects with the A468 in Caerphilly. Thats the worse traffic going. Same up Merthyr

[@dougdavidson175]

Another wicked sweet video John. So, of course, I hit the button specifically for that! Take care & stay safe.

[@douglasnelson3569]

Drinking game - every time John says 'roundabout', drink a shot glass of cider :D

[@garionallen]

Amazing video. I’m from Cardiff and I didn’t even know about the old junction and I’ve been through/around that roundabout countless times over the years!

[@CSMSoundLight]

I’m just up the valleys, and I also never Knew about the old layout

[@gavingilbert8510]

I've driven it dozens of times and never noticed I was on a roundabout. There again, it could because I was grateful to be leaving Cardiff....

[@paulsengupta971]

I don't understand how you wouldn't notice you were on a roundabout...it seems quite obvious to me! But then again I've been using this junction since I was a kid!

[@benllewelyn98]

But potentially heading towards Merthyr which is wholly worse

[@Beliefisthedeathofintellect]

Cardiff is actually a good city compared to some pretty shyty English cities I know.

[@SabotsLibres]

There is at least one other “over and under” roundabout (a real one too) in the UK on the A45 Coventry Road where it crosses the M42 at the Bickenhill Interchange

[@andymerrett]

I love the "because reasons" - succinct :)

[@Jon-em4kc]

The addition of the short link from the Westbound off slip onto the A470 has transformed the junction. Still ridiculously busy at peak times, but better. Now they just need to sort out the A470 to stop that bottlenecking at the Caerphilly and Nantgarw interchanges, which will improve the M4 again!

[@marksmith2276]

And again at Abercynon. That roundabout is begging for a flyover or underpass as most of the traffic is continuing up towards Merthyr. Spending all the money on the A465, which will just make it worse.

[@solsnapper2141]

To coin a phrase;- Good luck with that!

[@AintBigAintClever]

@@marksmith2276 to be fair the bottleneck at Abercynon is usually because someone's flipped their car outside Trade Centre Wales.

[@ianstewartorr8455]

The A 470 goes all the way to Llandudno a lovely part of wales greetings from Scotland 🇬🇧🇬🇧🇬🇧

[@martinjones5560]

Negotiated this roundabout last week. Only got in the wrong lane twice!

[@cdl0]

Agreed, the two-minute bonus item at the end of this video is brilliant! 🙂

[@hairyairey]

Average speed of 30mph is pretty good for a roundabout!

[@richardsanders7906]

The road you joined from in the end circuit was the original A470 going through Tongwynlais. I can remember driving through there as it was then and all the various evolutions of that interchange since.

[@paulsengupta971]

They've killed that road through Tongwynlais now, it's a nightmare...bumps, chicanes, narrowings. Awful! And I only go in there to a friend's mother's house.

[@slimey99uk]

This roundabout used to be on my commute to/from the office (which was up the A470). The one bonus was the McDonalds half way round, which would be a regular stop for breakfast on the way to the office :)

[@MabDarogan2]

It's worth mentioning that the South Wales Traffic Management Centre lives in the roundabout. That's how big it is.

[@AmirBrooks]

You got VERY lucky with the lights and traffic there. If you wanted to turn from the A470 southbound onto the M4 westbound at rush hour, you'll probably be stuck on that roundabout for a good 10-15 minutes.

[@WagnerGimenes]

That was bloody good, yes.

[@DavidPaulMorgan]

As a Newport boy, living in Cardiff and having been a regular M4 commuter over the years, I learned something new!

[@ChrisHopkinsBass]

The dedicated filter is there to stop traffic backing up on the eastbound M4. It used to be quite bad back in the day

[@paulsengupta971]

It doesn't hurt that they've now got two lanes coming off the M4 there.

[@Chriswales]

Remember the day that filter lane opened. They got the traffic light timing wrong and I was stuck on Northern avenue for over an hour trying to get onto the M4.

[@ChrisHopkinsBass]

@@paulsengupta971 as long as everybody uses their common sense when you get to the A470 slip road for eastbound M4 trafic about 500 yards down from the traffic then it's not too bad.

[@whelkschance]

The connection from the west going north is very useful if you live in north-west Cardiff and are coming home from fhe Swansea direction. North Cardiff is basically missing an M4 connection so this lets you move quickly off the motorway up to Radyr without needing to join all the traffic lights you've mentioned.

[@origin178]

Great video! I used to walk around this roundabout every lunchtime, until Covid struck and WFH became permanent. I've crunched around in the snow, rain, and baking heat. It's like a forgotten nature reserve known only by a few locals, cyclists, and some very large birds (feathered variety). I always wondered why such a huge underpass had been built just for a footpath, and the other mysterious concrete wall a few meters further on!

[@TheMorningDawnTMD]

almost all greens on the roundabout tour. impressive

[@brokenbritain9441]

What you forgot to mention it's probably the only roundabout with a speed camera on it😮

[@mikeuk666]

That is a red light camera

[@brokenbritain9441]

@@mikeuk666 🙈

[@hedydd2]

It’s a roundabout, but not as we know it Captain. I’m fairly sure that Radio Wales calls it the Coryton ‘Interchange'. Unless that’s another bit of road entirely.

[@danteeightsix9069]

The ending reminds me of the GT time trials where you have to pass as many cars as possible.

[@RichardMigneron]

Love you Jon. You bring laughs everytime to brighten my day.

[@shaun30-3-mg9zs]

Hi Jon looks like you had a good time, go on treat your self one more lap of this roundabout i've only been on this junction once it was fun that must have been 2016 on my way to Cardiff. Great video take care

[@SuperRobertwillis]

Wow John that was overwhelmingly exciting 😂😂😂😂😂😂❤

[@chrisstewart7420]

One of your best yet, john. The comments prove it 2 minutes to go round a roundabout amazing and ridiculous 😅

[@Broadsword999]

If you went about 5 miles north there is a big roundabout on the A470 at Treforest Industrial estate.

[@rebmcr]

A mere ⅓ mile around.

[@paulsengupta971]

At Upper Boat?

[@mikeuk666]

the triple layer roundabout further down from this roundabout is interesting

[@paulsengupta971]

@@mikeuk666 Further down? The Gabalfa flyover?

[@chrishartley1210]

Although not the biggest roundabout/interchange, the one at J27 of the M62 must be one of the longest, timewise, to negotiate depending on your entry or exit points. In comprises junctions with A650, A62, M621 and of course M62. It can take about 7 minutes to go from A650 eastbound to A62 southwest. Of course, anyone with local knowledge wouldn't take that route but if you originally missed your turning (easily done) and need to make the full circuit you can add another couple of minutes. It is of course a dumbell interchange, no doubt getting such a description from the person who designed it.

[@getreal7964]

So bloody good I went for a 2nd lap...most enjoyable 4 mins today ! 😊

[@doctordeej]

Impressive roundabout - almost a ring road, all it needs is a small village in the centre. Well, there’s room for one.

[@allymac1314]

That outro music was funky AF. Wicked bass line.

[@chrispenn715]

I live locally - that was the quickest lap I've ever experienced! 😂😂

[@mothmagic1]

Thanks for this mate. Probably the most entertaining and informative video i'll watch today.

[@MrBreadman1966]

I can remember back in the 80`s the science programme "Tomorrows World" drove around the M25 at around 100MPH to demonstrate it just before it was opened for the first time.

[@judeclancy1952]

bravo for the Gran Tourismo music at the end

[@ConfidentialMeerkat]

Took a shot every time John said roundabout now I can't see straight 😵‍💫

[@joshovki]

Driving it semi-regularly it actually works quite well. But I also know what lane I need to be in to be where, lots of people do get some what confused

[@tobyjackman3212]

Ooooh I've been wondering when you'll do this!? This is the best video I've ever seen about anything

[@joejarvis2497]

I love the music from Outrun.

[@maidbloke]

Worth a like for the real-time trip at the end 😍

[@rochellehewston9367]

The amount of research that you do for our benefit is amazing John I’m so grateful. I’ve been through that junction on the M4 but was not aware of any of the information you gave us today. so thank you again.

[@iankendall4837]

i love these videos, i just wish there were more motorways so 'secrets of the motorway' could carry on!! i loved the one about the A40 park and ride, everyday i go past it and just think that could have been spent on a wider road! 😂

[@pgriffithsulster]

I feel old. I remember the old Tongwynlais junction. When the M4 opened, it terminated at this roundabout as they had not built the bit around the top of Cardiff. We would come down the A470 and then around the roundabout and join it westward. I think all the motorway bridges were built - unlike what happens today, the A465 at Gilwern - but it took a few years for them to finish off the Cardiff-Newport section. Then there were no lights on the roundabout, but then it was the 1980s.

[@GMteam.]

i remember the m4 ending at tredegar park. then a big gap past cardiff. pretty sure it started again down swansea way.

[@mikeuk666]

The two newer adjustments to it have made a huge difference

[@braderzjamez3197]

The gran Turismo music brings back some memories. Another great vid 👍🏾👍🏾

[@enbysheriff]

I regularly cross this using the A470 going back and forth from my uni to my partner and ive never noticed anything that was mentioned

[@mRowden100]

This explains my confusion when I was going round this last year. I wondered why there was a monstrous one way system in place!

[@paulhowells6172]

I use that roundabout every day for work and often wondered what I looked like before the M4 , thank you also never knew there were old bits still in situ .

[@msn164]

I’m liking the dedicated single filter light on your chosen exit on its own pole. Something quite European about it.

[@willtricks9432]

Yes that was "Bloody Good", and the diving was also Tip Top!

[@sydnorth5868]

Yes, I can confirm having travelled around that roundabout many times that it is certainly the biggest roundabout that I have ever been round!

[@alantheskinhead]

My head hurts! Oh.... I just missed my train watching this! lol

[@ukmud6218]

That lap of the roundabout was definitely less painful than an episode of miranda

[@paulknight5018]

Such fun!!

[@stevehawthorne9918]

It’s definitely a roundabout. You’d be surprised the difference the extra slip road from the eastbound M4 to northbound A470 makes. I used to drive it regularly and it was a nightmare before that was built.

[@prich0382]

Should do a video on the M4 Junction 28 by newport, it's so awfully designed, like who thought that layout would be great, if you are used to it, then fine, but I remember first using it trying to get somewhere and I managed to take the wrong lanes twice before I got it right on the 3rd try, wasted half a hour going up and down the motorway.

[@antonycharnock2993]

Nice to see the lane markings are so clear and well marked out. I would never end up in the wrong lane on here. PS Can we have a video about J34 of the M1?

[@UK.RoadsCyclingandTransport]

I saw them build the new sliproad when I was 8 years old in 2014

[@paulsengupta971]

I can't believe it's been ten years since they added that "new" sliproad. Seems like just a couple of years ago to me!

[@UK.RoadsCyclingandTransport]

@@paulsengupta971 same, time flies, it's crazy that 2019 was over half a decade ago

[@axelBr1]

In The Midlands they call it a Circle, which throws you when trying to find your destination in the late evening having driven up from civilisation, in the days before GPS.

[@tentotwo8290]

I do love your informative and entertaining content, even your quirky presentation technique, but………… You fly through the deets soooo quickly that I have to watch them a few times to get my head around what you mean. Anyways, thanks 👍

[@EdwardKane-pb5rj]

The outro. Yes! More jazz funk please.

[@geoffbrett291]

You should try the drive round at 8am, it’ll take you a lot longer I guarantee

[@moaningpheromones]

erm, no that's ok

[@alexfelstead4330]

Watching a geezer talk about roads would usually be considered boring, but John’s sense of humour and personality make these what they are.

[@Loadarine]

I use this roundabout a lot as i live 15 miles away from it

[@drivewales]

To all the local bus service drivers trying to get up the A470 in the evening rush hour and watching their timetable evaporate at every red light. You have my deepest sympathy, been there done it, never doing it again!

[@NJRD977]

Stayed at the Holiday Inn on the north side of the junction far too many times for work when I had a site to run in Cardiff. Now stay there when I am visiting Bike Park Wales up the A470 at Merthyr because, well it is not Merthyr. Can recommend a trip up the full length of the A470 - fantastic trip though Wales

[@bobjackson6524]

Great vid as always

[@MENSA.lady2]

I believe the largest true roundabout is at the eastern end of the A31 Farnham Surrey bypass. So big that it has a few houses, a small holding and a pubb on it.

[@andymerrett]

Shepherd & Flock - It's certainly a contender. It is also likely quite rare in that it has a public exit "into" the roundabout (to access the pub etc.) - ie a right turn.

[@trinity8101]

Oh, I know the one you mean, the Farnham Racetrack 😁

[@MENSA.lady2]

@@andymerrett I used to live in Farnham and enjoyed a few beers in the Shepherd & Flock.

[@MENSA.lady2]

@@trinity8101 You just got a hole in 1.

[@paulfisher126]

0.5 mile for full circuit, so not as big as Coryton, but then it depends if Coryton really is a roundabout or not

[@markjlewis]

I know it well but I did learn about some things I hadn't noticed before. Will be having a look out for them next time I'm using it. Most locals as far as I know just refer to it as Coryton. There is a railway station just south of the roundabout with the same name. They take it from the Cory family that were big in to coal and shipping in South Wales back in the day.

[@mikephillis5013]

you got really lucky with them lights... usually you get stuck at every single one if one catches you...

[@bryansmith1920]

Love the Music in the finals, Mind you I kept expecting you to run into a Bulldozer Blade 😂😂😂

[@adamhaycroft5610]

I will have to shazam the music at the end for my own (partial) laps of the M4/A470 roundabout

[@paulsengupta971]

I prefer Fleetwood Mac's The Chain. Specifically the bit about three minutes in.

[@adamhaycroft5610]

@@paulsengupta971 🤣 are you secretly Nigel Mansell?

[@paulsengupta971]

@@adamhaycroft5610 I wish I had his money and talent!

[@adamhaycroft5610]

@@paulsengupta971 I'd be happy with either, or the ability to grow such a marvellous mustache 🤣

[@don1estelle]

The filter lane dose make a big difference because there are no Traffic lights!

[@pluxauag7555]

Well played on the video, and you avoided that left fork that takes you to the desert stage with the big mountains....the Cardiff stage of Out Run.

[@MrGreatplum]

I just watched a video about a roundabout didn’t I? And it was fun!

[@simonochana3189]

I’m sure that stretch of the A470 had motorway regulations. Definitely had a hard shoulder all the way to the end of the dual carriageway section, at Treharis, i think. Also had services at the top just before the roundabout at Treharis

[@dcvariousvids8082]

A 1min. circuit also depends on time of day and roadworks. I can’t bring myself to call it rush hour, that time when a mass of people decide to go home or to work or take their children to choir practice/tennis club,(which is a racket in itself)/insert other activity here, to replace the running, walking or cycling kids used to do. Before parents decided ‘their’ kids had to be protected from dust impacting the body, unless in a strictly controlled and expensively paid for environment. Back to the road junction/s - there’s times when the lights are green but one can’t proceed, as part of the system is locked or the whole thing is gridlocked. Leaving drivers to appreciate just how relaxing the sequence of lights can be, as the glowing circles change from red through the sequence and back to red, then repeats once or thrice, while traffic remains exactly where it was, before you started your transcendental enquiry into the nature of traffic signals. Then throw in roadworks with or without their own signals, plus local drivers who are very slowly constantly changing lanes, without the seeming need to indicate. Fortunately I very rarely travel that way now. So my own transcendental enquiry into the nature of traffic signals, is hardly ever given an outing.

[@annetteconroy6921]

That was a magic round about

[@1258-Eckhart]

Thanks for the full lap solely in the interests of science!

[@Anonymoususer_2023]

Was thinking if a tunnel would be built for the A4054 to pass underneath the M4 and A470. That would help local traffic to avoid the busy large roundabout.

[@Chriswales]

Been stuck in traffic there plenty of times. You didn't mention it's so big there's a traffic management depot inside it.

[@Madmark50484]

a missed opportunity! when going round the roundabout you should have played the magic roundabout theme song

[@liamames1247]

Thanks

[@CharityAngelSpectrum]

Roundatory? Gyrabout? Having just educated myself on wtf a gyratory is, this certainly qualifies. As do a couple of "roundabouts" near me. If nothing else, I have learned something today, so thank you.

[@chrisreadwells]

Done that 'roundabout' a lot, taking son to & from University of South Wales just off A470 at Pontypridd.

[@terot8341]

This has been most shortest and hardest drinking game so far. But I managed to finnish the roundabout

[@acespark1]

I am great ! Thanks for asking and I am subscribed and that is wicked sweet and awesome. I also liked the vlog so I used the button specifically for that 😁

[@ljw5768]

Use it all the time. I’m a master of the lanes you don’t really need to be in yet they make you get around it faster.