BIB - I assume you mean A3M - but that's not correct. The only bit of the A3 designated as the A3M is Horndean where it joins the A27.
A3 road - Wikipedia
en.wikipedia.org
I wouldn't have thought that would be a problem - as long as the signs make it clear that non-motorway traffic should stay on the A3 and not turn off.
BIB - I assume you mean A3M - but that's not correct. The only bit of the A3 designated as the A3M is Horndean where it joins the A27.
A3 road - Wikipedia
Yes. Perhaps I should explain:
Highways England like to add "AP" to show that it isn't a motorway, but no-one else does.
That's definitely a mega junction
I've driven that one a few times too. Deceptively fiendish but it's got a lovely flow to it which is extra nice with the valley rising on both sides..pretty dramatic. Still prefer taking the pass via Amtrak though!
Done that myself a couple of times - loco headlights illuminating the rock formations at night as you climb...
At some point in the future I'm going to go on a USA trip, both to see their rail network and (getting back on topic!) road network. I could probably easily spend years exploring...Done that myself a couple of times - loco headlights illuminating the rock formations at night as you climb...
The better 'enthusiast' road to take is Cajon Blvd of course (a remnant of old 'Route 66') - you can pace the frequent double-stack trains climbing out of out of San Bernardino at the bottom and then take your pick of pull-offs further up to watch (and listen to) them go by...
I think you have hit my area of expertise here. From what I know around Manchester and Cheshire, is that the junctions are different, and generally more complicated and selective. For example the M56/M6 junction near Lymm in Cheshire, has restricted answer so E - S slip road doesn’t exist. Whereas Germany and USA are more simple, the British Planners are more inclusive of all the roads and different journeys. To elaborate, the junctions abroad are more geometric like the cloverleaf, the British ones are built to match the terrain or landscape, avoid certain buildings, or include other roads e.g (again) the M56/M6 junction where access is given to the A50, however it might pan out differently in different countries: they could build junctions in different positions, or avoid building junctions due to cost cutting. I would compare the UKs motorway junctions to ones of urban America e.g the Newark airport junction and lots more.Following on from the London Ringways thread, the topic of cloverleaf junctions came up.
For those of you who haven't (yet!) reached the point where road junctions are a really exciting topic (), here's a diagram of one for you to look at:
View attachment 94050
There are only two examples in the UK, in Redditch and in Livingston (the next junction north from this used to also be a cloverleaf, but for some reason was changed to what it's like now). Neither are on what could be termed as fast, high capacity or strategic roads, which may explain their limitations. In continental Europe and North America however, they are very common: in Germany, for example, it's very difficult to find a 4-way Autobahn junction which isn't either a cloverleaf, used to be a cloverleaf but has since been upgraded, of is a cloverleaf-derivative - and these examples are often only different because of limiting geography, such as this one. There are also amusing examples, such as here, where the road was quite clearly meant to continue north through the cloverleaf, but was never built, resulting in a bodge.
The main issues with cloverleaves are that traffic coming off one loop has to cross over traffic leaving via the next loop, with horrendous consequences for capacity as a result, the tight loops, and the large land-take. They are, however, easy and cheap to build (only one bridge): I think this is the main reason why they're so prevalent in countries like Germany with very old motorway networks - there are comparatively few engineering challenges. And the land take isn't too much of an issue: if you were a 1930s German landowner, would you say nein to der Fuehrer? Probably not! In the USA, land is plentiful, hence the large number of cloverleaves.
The weaving problems caused by cloverleaves can be substantially reduced by adding parallel carriageways for turning traffic - virtually all German cloverleaves have been upgraded in this way. You can even do this - a fully grade-separated cloverleaf - but obviously that's only been done because ripping out the existing junction and replacing it with something more suitable would be far too disruptive.
Having rambled on for far too long by now, I've forgotten the point I was going to make!
(This thread isn't just limited to cloverleaf junctions, by the way, fee free to discuss other designs!)
A bit like the A1(M)/M62 junction at Ferrybridge: three turning movements are facilitated by the new free-flow bit, but if you want to go between south and east you have to use the old junction; this is because most long distance traffic uses the M18!
Leading up to any major motorway junction like the one you have just mentioned should be given the largest priority, and of course ring roads. On the M60 especially the junctions are quite unique and different such as, Junction 3, 5, 6, 7, 8, 11 & 12, 14, 15 & 25, 26. These are formed to fit the existing road, and I’m sure they are examples on the M25. The upgrading of the M60 was one of the best highway upgrades in the North West since I can remember.
Also the M4/M5 junction north of Bristol. There are only three of these 4 level stack junctions in the UK; compare that with Los Angeles... : D
That's because the M11/M25 junction isn't a roundabout! It's a "whirlpool" junction.
Yes thanks - I remember being able to see where I wanted to go, but couldn't get over.
Absolutely, and I usually went this way in preference to the A556; now that I live in Wilmslow I drive across to M6 J18 (if I want to go S on the M6) rather than use the M56 and also I haven't used the rebuilt A556 which probably is quite an improvement over the old road I tended to avoid.
Always worth checking SABRE: https://www.sabre-roads.org.uk/wiki/index.php?title=Townhill_Link_Motorway
That roundabout is being obliterated by HS2 - the line goes literally straight through the middle!
I read somewhere that the original plan for the M6 was to run it somewhere much closer the what is now the M6 Toll, but the authorities of Birmingham lobbied (successfully) for the route to be moved much closer to the city centre (mainly so they didn't have to build their own "local" motorway). I wonder what the road network would look like today if the M6 followed the originally-planned route?
The junction in Plymouth, north of the city centre, between the B3413 (which was once the A38) and the A386, is also logically a cloverleaf, though a very unusual one.Following on from the London Ringways thread, the topic of cloverleaf junctions came up.
For those of you who haven't (yet!) reached the point where road junctions are a really exciting topic (
View attachment 94050
There are only two examples in the UK, in Redditch and in Livingston (the next junction north from this used to also be a cloverleaf, but for some reason was changed to what it's like now).
That's because there is a stubborn farmer's buildings in the path of where that slip road would be.
I favour whirlpools the most. There's another example where the M602 meets the M60 & M62, but they're rarer than I'd like in the UK.
