Why do they deliberately obscure vision at roundabouts?
Discussion
Cotty said:
TurboHatchback said:
I'm afraid I don't share your fundamental faith in organisations only doing things because they make sense. I see countless examples of quite the opposite.
Do you work for the same company as me?
. otolith said:
I wonder if anyone has calculated the increase in CO2 emissions caused by forcing people to drive less efficiently?
I doubt it, those who end up in governmental positions responsible for complaining about CO2 and such don't seem to be troubled by inconveniences such as physics and logic. otolith said:
I wonder if anyone has calculated the increase in CO2 emissions caused by forcing people to drive less efficiently?
You're not being forced to drive less efficiently. You can CHOOSE to drive less efficiently by roaring up to the junction, anchoring up, and roaring away, but you're aware of a give way (as is at the entrance to every roundabout in the country) so can adapt your driving to suit. You don't even HAVE to go that way, you can choose another route altogether if you want. OpulentBob said:
otolith said:
I wonder if anyone has calculated the increase in CO2 emissions caused by forcing people to drive less efficiently?
You're not being forced to drive less efficiently. You can CHOOSE to drive less efficiently by roaring up to the junction, anchoring up, and roaring away, but you're aware of a give way (as is at the entrance to every roundabout in the country) so can adapt your driving to suit. OpulentBob said:
You don't even HAVE to go that way, you can choose another route altogether if you want.
Because taking a less direct route does not increase CO2 emissions, does it?otolith said:
OpulentBob said:
otolith said:
I wonder if anyone has calculated the increase in CO2 emissions caused by forcing people to drive less efficiently?
You're not being forced to drive less efficiently. You can CHOOSE to drive less efficiently by roaring up to the junction, anchoring up, and roaring away, but you're aware of a give way (as is at the entrance to every roundabout in the country) so can adapt your driving to suit. OpulentBob said:
You don't even HAVE to go that way, you can choose another route altogether if you want.
Because taking a less direct route does not increase CO2 emissions, does it?I can drive 51 miles home on the motorway in an hour and get 50mpg and probably pretty good CO2, or 31 miles on back roads in a similar time, get 35mpg and produce more CO2 than I otherwise would.
re. Driver behaviour - again, that's for the individual driver to worry about. You're free to race up to every stop/give way line and anchor up at the last minute. You're free to pull away as fast as you like. If you're THAT worried about CO2, then you'd drive accordingly.
OpulentBob said:
re. Driver behaviour - again, that's for the individual driver to worry about. You're free to race up to every stop/give way line and anchor up at the last minute. You're free to pull away as fast as you like. If you're THAT worried about CO2, then you'd drive accordingly.
I think the point being made though is that people having to slow down to a stop and then accelerate away, (note - no mention of racing away or slamming on the anchors but just driving normally), when they could have cruised through at a steady speed in a sensible gear produces more CO2.OpulentBob said:
re. Driver behaviour - again, that's for the individual driver to worry about. You're free to race up to every stop/give way line and anchor up at the last minute. You're free to pull away as fast as you like. If you're THAT worried about CO2, then you'd drive accordingly.
If you, as someone responsible for designing the road system, design a feature in such a way that road users will typically drive less efficiently than they could do, that's your fault. Same as if you design it in such a way that you make it more likely that they will make mistakes and crash. You can't wash your hands of it by saying it is up to them, because if you really felt like that you wouldn't be sabotaging the visibility in the first place. In this case you might be willing to say that you have increase CO2 emissions in order to reduce crashes, which might be fair enough, but you should still do the maths.
OpulentBob said:
Oh hang on. They DO have a benefit? Make your mind up.
Do you not think that years of research, modelling and design might possibly have some benefits, and have some grounding in fact? Or, should we leave it all to armchair experts and DM/PH readers, and scrap the TRL? Are you actually aware of the HUGE increase in vehicle ownership and traffic figures over the last 20-40 years, and the impact it has on the road network?
I was making a sweeping statement deliberatly, then made a point to show some awareness that they aren't necessarily useless in every circumstance - there are always exceptions, and it would have taken more words than I wanted to type to make a coherent, rational explanation of my view, so I didn't bother. I agree with your final point, but I will add this - the law of unintended consequences is very apparent with some traffic management 'solutions'.Do you not think that years of research, modelling and design might possibly have some benefits, and have some grounding in fact? Or, should we leave it all to armchair experts and DM/PH readers, and scrap the TRL? Are you actually aware of the HUGE increase in vehicle ownership and traffic figures over the last 20-40 years, and the impact it has on the road network?
Hangcheck said:
OpulentBob said:
re. Driver behaviour - again, that's for the individual driver to worry about. You're free to race up to every stop/give way line and anchor up at the last minute. You're free to pull away as fast as you like. If you're THAT worried about CO2, then you'd drive accordingly.
I think the point being made though is that people having to slow down to a stop and then accelerate away, (note - no mention of racing away or slamming on the anchors but just driving normally), when they could have cruised through at a steady speed in a sensible gear produces more CO2.otolith said:
OpulentBob said:
re. Driver behaviour - again, that's for the individual driver to worry about. You're free to race up to every stop/give way line and anchor up at the last minute. You're free to pull away as fast as you like. If you're THAT worried about CO2, then you'd drive accordingly.
If you, as someone responsible for designing the road system, design a feature in such a way that road users will typically drive less efficiently than they could do, that's your fault. Same as if you design it in such a way that you make it more likely that they will make mistakes and crash. You can't wash your hands of it by saying it is up to them, because if you really felt like that you wouldn't be sabotaging the visibility in the first place. In this case you might be willing to say that you have increase CO2 emissions in order to reduce crashes, which might be fair enough, but you should still do the maths.
Otherwise, see my previous post.
RenesisEvo said:
OpulentBob said:
Oh hang on. They DO have a benefit? Make your mind up.
Do you not think that years of research, modelling and design might possibly have some benefits, and have some grounding in fact? Or, should we leave it all to armchair experts and DM/PH readers, and scrap the TRL? Are you actually aware of the HUGE increase in vehicle ownership and traffic figures over the last 20-40 years, and the impact it has on the road network?
I was making a sweeping statement deliberatly, then made a point to show some awareness that they aren't necessarily useless in every circumstance - there are always exceptions, and it would have taken more words than I wanted to type to make a coherent, rational explanation of my view, so I didn't bother. I agree with your final point, but I will add this - the law of unintended consequences is very apparent with some traffic management 'solutions'.Do you not think that years of research, modelling and design might possibly have some benefits, and have some grounding in fact? Or, should we leave it all to armchair experts and DM/PH readers, and scrap the TRL? Are you actually aware of the HUGE increase in vehicle ownership and traffic figures over the last 20-40 years, and the impact it has on the road network?
otolith said:
So someone is doing the maths, or at least should be.
Yep, if a scheme affects traffic flows - such as areduction in speed limits - then the environmental health team can monitor air quality levels, if deemed necessary. More necessary next to a school and housing estate than a junction off a motorway 10 miles from the nearest house. But a hybrid/small diesel if you're that worried, rather than a 14 cyulinder fleet.
Wow, quite a few PH'ers getting quite steamed up about some road design they don't consider to be sensible. We all have the opportunity to influence this - anything that needs planning approval is open to public comment - put your 2p in - but please remember that road design, and approvals, are partly commercial, partly engineering, and partly political.
If we don't want to comment on the approval, then we can become a road engineer and come up with the standards used. If we don't want to do that, then we can become a politician/councillor and lobby for certain changes. Don't just sit there and whinge because you don't like being able to straight line a roundabout.
Road designers are given a set of standards, and asked to make the traffic flow as per the political decision - whatever ring road has been promised, or widening, or whatever. I would have thought that members of this forum would be more aware of some of this process, seeing as we all think of ourselves as enthusiasts. Safety is always above CO2 emissions, and whilst it might seem hard to understand, slowing the entry to a roundabout does make it safer to negotiate for all - both those on the roundabout and those trying to enter.
If we don't want to comment on the approval, then we can become a road engineer and come up with the standards used. If we don't want to do that, then we can become a politician/councillor and lobby for certain changes. Don't just sit there and whinge because you don't like being able to straight line a roundabout.
Road designers are given a set of standards, and asked to make the traffic flow as per the political decision - whatever ring road has been promised, or widening, or whatever. I would have thought that members of this forum would be more aware of some of this process, seeing as we all think of ourselves as enthusiasts. Safety is always above CO2 emissions, and whilst it might seem hard to understand, slowing the entry to a roundabout does make it safer to negotiate for all - both those on the roundabout and those trying to enter.
OpulentBob said:
otolith said:
So someone is doing the maths, or at least should be.
Yep, if a scheme affects traffic flows - such as areduction in speed limits - then the environmental health team can monitor air quality levels, if deemed necessary. More necessary next to a school and housing estate than a junction off a motorway 10 miles from the nearest house. But a hybrid/small diesel if you're that worried, rather than a 14 cyulinder fleet.
The environmental health team won't pick up CO2 emissions, they aren't a local air quality issue. I'd have thought you would have a computer model for the changes in CO2 emissions due to road engineering.
otolith said:
OpulentBob said:
otolith said:
So someone is doing the maths, or at least should be.
Yep, if a scheme affects traffic flows - such as areduction in speed limits - then the environmental health team can monitor air quality levels, if deemed necessary. More necessary next to a school and housing estate than a junction off a motorway 10 miles from the nearest house. But a hybrid/small diesel if you're that worried, rather than a 14 cyulinder fleet.
The environmental health team won't pick up CO2 emissions, they aren't a local air quality issue. I'd have thought you would have a computer model for the changes in CO2 emissions due to road engineering.
How powerful would computers have to be to calculate the aditional CO2 from anything up to 90000 cars a day, all different engine sizes, fuel types, emission controls, etc?! It's not practical, nor is there software that I am aware of to work it. Again, I reiterate, I (and 99% of highway design engineers) design for safety and NOT for emissions. To design for emissions would have 56mph speed requirements everywhere, and buses and lorries and pedestrian crossings would be banned from any urban areas. (OK, a bit extreme, but if you start designing for emissions, that's the sort of crazy proposals you'd get from the green fringes)
ETA that's me done for the day/week. I've given information where possible, if it's not good enough then sorry, get in touch with your local MP, and get him to put pressure on the DfT to change things.
I'm going to go and rag my car all the way home on the back roads! Have a good weekend.
Edited by OpulentBob on Thursday 17th April 15:10
Environmental health are very interested in CO, CO2 is fairly irrelevant to them.
A computer model for estimating the effect of road engineering on traffic emissions would not be that difficult to do. It's the sort of thing my former colleagues at a civil engineering consultancy would have had no problem building more than a decade ago. It's not that much more complex than the thing I got roped into building for estimating train performance and fuel consumption. I would be amazed if it hasn't already been done.
Have a good weekend!
A computer model for estimating the effect of road engineering on traffic emissions would not be that difficult to do. It's the sort of thing my former colleagues at a civil engineering consultancy would have had no problem building more than a decade ago. It's not that much more complex than the thing I got roped into building for estimating train performance and fuel consumption. I would be amazed if it hasn't already been done.
Have a good weekend!
M40 J10 northbound they have a high fence ti block visibiliy on the roundabout. In the years before it was installed i dont recall ever seeing an accident (and i use it every day). Since it was put in i have seen 2 lorries on their sides from trying to go too fast around it. Probably coincidence , not sure why a barrier would have HGVs speeding up.
And it doesn't slow me down, you can get a good look at the bridge to check for traffic before you reach the barrier, then just be ready to anchor up if you reach the roundabout and someone is there unexpectedly.
And it doesn't slow me down, you can get a good look at the bridge to check for traffic before you reach the barrier, then just be ready to anchor up if you reach the roundabout and someone is there unexpectedly.
TurboHatchback said:
On many roundabouts with dual carriageway approaches there seems to be fences or other visual obstructions put in place for no other purpose I can see but to block peoples view of the traffic until they are right on the roundabout.
Case in point: Google map link
There is some back story to the barriers in Cadnam. Motorcyclists had noticed that the two roundabouts (the one in your link and the motorway roundabout connected by a 200yd stretch of dual carriageway) contained a very entertaining sequence of bends. It's on the route down to the Poole Quay bike meet, and you can imagine that if every Tuesday night you get 5/10 bikers doing laps of the two roundabouts, the local residents would start complaining.Case in point: Google map link
So they ended up putting in those barriers and cut the speed limit from 70 to 50mph.
You can get a gist of it if you search for Cadnam GP Circuit
Edited by njd27 on Wednesday 23 April 12:17
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