Do Sheffield City Council Have Something Against Roundabouts ?

[Chekhov]

Or, to put it another way, why do Sheffield City Council seem to love traffic lights so much ? 

They seem to insist on putting in traffic lights when a roundabout (even just a "mini roundabout" if space is short) would work much better.

The only advantage I can think of for a set of traffic lights (or a conventional junction) over a roundabout would be ease of crossing the road for pedestrians (particularly if a zebra crossing of light controlled crossing is involved). Or am I missing something ?

 

As a supplementary question have the esteemed members of this forum got a particular junction they think would work far better as a roundabout ?

 

Of the routes I use a lot my suggestion would be the junction of Wheel lane/ Saltbox Lane and Halifax Rd/Penistone Rd up at Gleadles, though Dykes Hall Rd/Far lane would be up there too.

Also, for a non traffic controlled junction, Bracken Hill/Burncross Rd in Chapeltown, I am surprised there aren't more accidents there TBH.

[HeHasRisen]

Think I read somewhere that traffic lights are much better at junctions where the traffic flow across it is uneven. This is clearly one for @Planner1 to answer fully.

 

Its not just Sheffield tbf. In my boyhood town two notable roundabouts have been replaced in the last ten years by a normal traffic junction.

Edited August 16, 2023 by HeHasRisen

[ads36]

roundabouts take up a lot of space, and that's expensive.

 

a traffic light controlled crossroads can be set to include pedestrian crossings in the timings.

[Chekhov]

37 minutes ago, ads36 said:

roundabouts take up a lot of space, and that's expensive.

 

a traffic light controlled crossroads can be set to include pedestrian crossings in the timings.

How much more space do mini roundabouts take up ?

 

I agree about the pedestrian crossings, as I said in the opener, but surely they could be accommodated somehow, even if it's just  a but further down the road(s) ? 

[HeHasRisen]

Without looking it up, I would say light controlled flat junctions create less RTAs than roundabouts (even ones controlled by lights). I cant prove this though, maybe I am wrong.

Edited August 16, 2023 by HeHasRisen

[ads36]

50 minutes ago, Chekhov said:

How much more space do mini roundabouts take up ?

not much, but very low capacity.  you're not going to get 2000 cars an hour through a mini-roundabout.

 

50 minutes ago, Chekhov said:

I agree about the pedestrian crossings, as I said in the opener, but surely they could be accommodated somehow, even if it's just  a but further down the road(s) ? 

yes, that seems to be how it's done when there is a roundabout.  but if we ask pedestrians to walk too far* to the crossing, they'll just ignore the crossing, and attempt to cross in a straight line, ad-hoc basis.

(*there is probably an industry-acknowledged upper-limit for this distance... i would guess even only 20metres would be getting into 'sod that' territory)

Edited August 16, 2023 by ads36

[dave_the_m]

Roundabouts are good at minimising delay during light usage (you're not sitting at red while no other traffic is doing anything) and

maximising traffic flow during heavy usage. But they are not good at ensuring fairness during heavy usage. For example, you can end up with a constant stream of traffic going N->S while people coming from E queue endlessly, because unless a car going to E comes along, nothing stops the flow of cars from N. So sometimes traffic lights can make a roundabout operate more fairly, hence why you sometimes get peak-only traffic lights on roundabouts.

 

In general, roundabouts are safer. You may get collisions, but they tend to be slow-speed bumps - rather than someone going into the side of you at 40 mph, which can happen if someone doesn't see a red light.

[Chekhov]

1 hour ago, ads36 said:

not much, but very low capacity.  you're not going to get 2000 cars an hour through a mini-roundabout.

Surely that'd do for Bracken Hill/Burncross Rd in Chapeltown ? As I said I am surprised there aren't more accidents at that cross roads as drivers have to look in three different directions at the same time, then work out who is going to go.

 

1 hour ago, ads36 said:

yes, that seems to be how it's done when there is a roundabout.  but if we ask pedestrians to walk too far* to the crossing, they'll just ignore the crossing, and attempt to cross in a straight line, ad-hoc basis.

(*there is probably an industry-acknowledged upper-limit for this distance... i would guess even only 20metres would be getting into 'sod that' territory)

Surely it's just as likely they'd cross anyway rather than wait for the "green man" ?

Speaking as a pedestrian I'd rather walk 20 yards to a Zebra crossing than wait for a green man with no indication how long it'll be since we have never really gone in for light timers in this country. Plus there's always a chance one would be walking down that rod anyway ?

 

1 hour ago, dave_the_m said:

In general, roundabouts are safer. You may get collisions, but they tend to be slow-speed bumps - rather than someone going into the side of you at 40 mph, which can happen if someone doesn't see a red light.

I agree with this, generally anyway, you still get ****holes tearing onto roundabouts, esp big ones.....

Edited August 16, 2023 by Chekhov

[Planner1]

2 hours ago, Chekhov said:

Or, to put it another way, why do Sheffield City Council seem to love traffic lights so much ? 

They seem to insist on putting in traffic lights when a roundabout (even just a "mini roundabout" if space is short) would work much better.

The only advantage I can think of for a set of traffic lights (or a conventional junction) over a roundabout would be ease of crossing the road for pedestrians (particularly if a zebra crossing of light controlled crossing is involved). Or am I missing something ?

 

As a supplementary question have the esteemed members of this forum got a particular junction they think would work far better as a roundabout ?

 

Of the routes I use a lot my suggestion would be the junction of Wheel lane/ Saltbox Lane and Halifax Rd/Penistone Rd up at Gleadles, though Dykes Hall Rd/Far lane would be up there too.

Also, for a non traffic controlled junction, Bracken Hill/Burncross Rd in Chapeltown, I am surprised there aren't more accidents there TBH.

Junctions on public highways are designed in accordance with government guidance, which tells the designer what type of junction is most appropriate for the traffic movements and volumes.

 

The needs of all road users have to be considered, not just motorists.

 

On busy main roads nowadays, it’s usually a signalled junction arrangement that fits the bill.
 

That allows the introduction of signalled crossings for pedestrians and cyclists and gives the potential to manage the traffic flows more efficiently, including giving priority to public transport.

 

Roundabouts are less space efficient as it is necessary to “flare” the approaches to create an angled entry onto the roundabout. Roundabouts are often less efficient in “tidal” traffic situations, ( like in the morning or evening peaks) where one predominant high volume traffic flow dominates the roundabout, making it difficult for traffic on other entries to get onto the roundabout.

 

Mini roundabouts are ok on quieter roads but aren’t recommended on busy main roads but again they need more space.

 

Obtaining land is a big issue for highway schemes. It can take years of effort to obtain land either by negotiation or compulsory purchase. Land is costly and increased cost lowers the benefit/cost ratio ( which is important to funders)  and therefore can damage the business case for the scheme. Need for land purchase is a risk and it can delay the scheme, again increasing costs, which is undesirable.

 

The less risky and quicker approach is to build within the existing highway boundary, which can often mean a signalled junction is the only viable option. But, in a large scheme, all the potential options will be considered in the optioneering process that takes place early in the schemes development 
 

Nowadays, promoting a shift to walking and cycling is very important, especially to the government, who basically provide most transport funding. It’s therefore important to consider the needs of cyclists and pedestrians and their safety, so providing segregated, signalled crossings which are actually on the “desire line” ( people’s normal direction of travel) will be an important consideration in any scheme. So, putting in a crossing “somewhere up the road” isn’t a reasonable proposition.
 

Much of the government funding available to local authorities nowadays is targeted at walking, cycling and public transport. Some funding streams are now starting to explicitly state that schemes cannot provide extra capacity for general traffic.

[Chekhov]

39 minutes ago, Planner1 said:

Junctions on public highways are designed in accordance with government guidance, which tells the designer what type of junction is most appropriate for the traffic movements and volumes.

Would that be the same government who insist on temporary traffic lights (or even road closures) when they aren't even needed ?

More specifically, as regards roundabouts, Milton Keynes seems to do alright....

 

39 minutes ago, Planner1 said:

Some funding streams are now starting to explicitly state that schemes cannot provide extra capacity for general traffic.

What a surprise, not.

How can anyone say this government is not anti-car ? And that's the Tories, I would expect Labour to be even worse.

But at least being told about it is performing a valuable democratic function.

Edited August 16, 2023 by Chekhov