[spesrf25]

I was reading the Motorway Speed Limit Thread and thought of this:

I'm obviously not British, so I haven't grown up using round-a-bouts all of my life. I have been here a couple of years, and I am now used to them, and they make sense in a lot of places, but what popped up in my mind is, what in the heck is the purpose of a friggin roundabout in the middle of a high-speed, high-traffic Motorway or Carriageway???? Why not have on and off ramps? All they seem to do is clogg up traffic.

[dxb335d]

Originally Posted by spesrf25

I was reading the Motorway Speed Limit Thread and thought of this:

I'm obviously not British, so I haven't grown up using round-a-bouts all of my life. I have been here a couple of years, and I am now used to them, and they make sense in a lot of places, but what popped up in my mind is, what in the heck is the purpose of a friggin roundabout in the middle of a high-speed, high-traffic Motorway or Carriageway???? Why not have on and off ramps? All they seem to do is clogg up traffic.

I dont think i know of any motorway with a roundabout, now dual carraigeways yes, its because dual carraigeways often lead to many many places and there maybe more of them and they go to craz places where as a motorway is one road which goes from one end of somewhere to another!!

you often pull off a motorway ''off ramp'' onto a dual carraigeway which inevitably comes to a roundabout which leads to an A-road to your destination do you agree??

The System seems ok to me, always room for improvement tho.

Carlos

[NFS]

Originally Posted by spesrf25

I was reading the Motorway Speed Limit Thread and thought of this:

I'm obviously not British, so I haven't grown up using round-a-bouts all of my life. I have been here a couple of years, and I am now used to them, and they make sense in a lot of places, but what popped up in my mind is, what in the heck is the purpose of a friggin roundabout in the middle of a high-speed, high-traffic Motorway or Carriageway???? Why not have on and off ramps? All they seem to do is clogg up traffic.

The issues are space, the relatively high cost of land in the UK and the cost to construct.

We are a small island and roundabouts are a very land efficient way of dealing with junctions quickly.

Concrete is also much cheaper in other countries (e.g USA), mainly due to supply of materials, so flyovers, ramps and other structures are also cheaper.

[dxb335d]

Originally Posted by needforspeed

The issues are space, the relatively high cost of land in the UK and the cost to construct.

We are a small island and roundabouts are a very land efficient way of dealing with junctions quickly.

Concrete is also much cheaper in other countries (e.g USA), mainly due to supply of materials, so flyovers, ramps and other structures are also cheaper.

And a darn sight UGLIER too.

[NFS]

Originally Posted by dxb335d

And a darn sight UGLIER too.

Yeah .. in contrast many roundabouts give me the horn.

[dxb335d]

Originally Posted by needforspeed

Yeah .. in contrast many roundabouts give me the horn.

Me too I love the way you can come out of the broadside

Carlos

[Mike UK]

Originally Posted by needforspeed

Yeah .. in contrast many roundabouts give me the horn.

sexy curves as well

[beemerbird]

Originally Posted by needforspeed

Yeah .. in contrast many roundabouts give me the horn.

I've now got this image in my mind of NFS standing in the middle of a roundabout practising self-gratification whilst muttering about undertaking.

Originally Posted by Mike UK

sexy curves as well

Now I'm really worried about some of you lot.

Personally, the roundabouts in full bloom are lovely and there should be nationwide competitions for the most colourful.

[SoYank]

Originally Posted by spesrf25

I was reading the Motorway Speed Limit Thread and thought of this:

I'm obviously not British, so I haven't grown up using round-a-bouts all of my life. I have been here a couple of years, and I am now used to them, and they make sense in a lot of places, but what popped up in my mind is, what in the heck is the purpose of a friggin roundabout in the middle of a high-speed, high-traffic Motorway or Carriageway???? Why not have on and off ramps? All they seem to do is clogg up traffic.

There are sliproads instead of roundabouts here that do exactly what you're talking about. They are used rather effectively, too. Two examples are the A1(M)/A14(M) at The Alconburys and the A14(M)/M11 at Cambridge. There are quite a few limited interchanges that have no roundabouts involved from one motorway to another (see M1/M18).

I can not imagine the confusion and chaos and carnage that would pile up if they had put a roundabout, magic or not, at the "mixing bowl" at I-95/I-495/I-395 south of Washington, D.C. instead of the flyovers: Springfield Interchange Map. For those not familiar with this interchange, there are three or four lanes northbound, three or four lanes southbound, and two or three segregated lanes for High Occupancy Vehicles (HOV-4) that shift direction; northbound in the morning, southbound in the evening.

Originally Posted by needforspeed

Concrete is also much cheaper in other countries (e.g USA), mainly due to supply of materials, so flyovers, ramps and other structures are also cheaper.

Originally Posted by dxb335d

And a darn sight UGLIER too.

Bear in mind, though, there are some interchanges here in the UK that look like they've been imported from the U.S. For example, from ground level, the A1(M)/M18 reminds me of the US101/I-280/I-680 interchange in San Jose, California.

[spesrf25]

Originally Posted by needforspeed

Yeah .. in contrast many roundabouts give me the horn.

Oh......now I understand! Now the answer is soo clear.....J/K....lol.

Thanks for the inputs...but I still don't get it. I'm pretty hard to convince or make understand about some things (hard headed).

[spesrf25]

I just did a search and from what I found, a big reason for them on daul carriageways is traffic calming. I don't see how causing major back-ups and idling cars instead of smoother traffic flow is beneficial, but at least I can see a reason for it.
Again, I do like roundabouts, and they do make sense in most places, but not during rush hour on a major carriageway.
Thanks again for the info

[Cafe.Racer]

Originally Posted by SoYank

There are sliproads instead of roundabouts here that do exactly what you're talking about. They are used rather effectively, too. Two examples are the A1(M)/A14(M) at The Alconburys and the A14(M)/M11 at Cambridge. There are quite a few limited interchanges that have no roundabouts involved from one motorway to another (see M1/M18).

Bear in mind, though, there are some interchanges here in the UK that look like they've been imported from the U.S. For example, from ground level, the A1(M)/M18 reminds me of the US101/I-280/I-680 interchange in San Jose, California.

I'd agree with that, especially the A1(M)/A14 and A14(M)/M11 (I guess you're "stationed" then?), but what about the A14(W) onto the A14(NW) at Cambridge?

Also, what about the A14/M1/M6 Catthorpe interchange - which muppet decided that we had to sit through god knows how long a set of reoad works to be blessed with that disaster.

Also, which dickhead thought it would be a good idea to connect the M1 to M40 (via Silverstone) with a loverly new dual carriageway that had flippin' roundabouts at either end? Madness.

A50 at M1 J24 - nice long slip road if you get off the M1(S) onto the A50 (which when you think about it is less than likely) but if you're going M1(N) and want the A50 you have to queue at one of the worst roundabouts (for traffic)...

Bah. I give up.

[NFS]

Originally Posted by spesrf25

I just did a search and from what I found, a big reason for them on daul carriageways is traffic calming. I don't see how causing major back-ups and idling cars instead of smoother traffic flow is beneficial, but at least I can see a reason for it.
Again, I do like roundabouts, and they do make sense in most places, but not during rush hour on a major carriageway.
Thanks again for the info

Traffic calming isn't a significant factor to my knowledge. Cost of land and structures (both to construct and maintain) are the key issues.

In the UK major roads are maintained by the highways agency and non trunk roads are maintained by local authority highways departments.

Both bodies would try to limit the extent an quantity of highway structures because they have significant maintenance costs.

Once you have ruled out absolute segregation, then roundabouts gain favour compared to signalised junctions because they improve traffic flows in comparison.