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Post by The Squeezed Middle on Oct 3, 2023 11:18:18 GMT
Well done Squeezed for at least trying to come up with a justification for not reducing the speed limit in cities like Plymouth from 30M PH to 20MPH. Pollution. OK where is your evidence that such a measure would increase pollution. It's the way vehicles work, Dippy. |
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Post by dappy on Oct 3, 2023 11:20:43 GMT
Can you read, Fairsociety? Yes, but it doesn't stretch no nonsense. Not sure exactly where my post failed to stretch no nonsense.... |
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Post by dappy on Oct 3, 2023 11:23:53 GMT
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Post by Dan Dare on Oct 3, 2023 11:24:51 GMT
The fundamental question appears to be the emissions per unit distance at 20 mph and at 40 mph.
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Post by dappy on Oct 3, 2023 11:26:28 GMT
Not sure the relevance of 40mph to the discussion Dan?
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Post by Fairsociety on Oct 3, 2023 11:27:04 GMT
Tell me about this journey through city streets where you can average 30MPH for the entire journey, Pacifico.
Not my experience tbh, I find traffic lights and pedestrian crossings and congestion tend to slow me down. So for a four mile journey I reckon with a 30mph limit it might take me around 15mins, with a 20mph limit maybe around 16mins. Does that sound about right to you. So add a 20 mph speed limit on that, it will 'slow you down' even more. Ok let's go over it.
Assuming when you approach 'traffic lights' and 'pedestrian crossings' and of course 'congestion', that tend to 'slow you down', you will be doing (hopefully) 20 mph or less in these scenarios, so you have basically just admitted that 20 mph zones cause congestion.
Yes, but it doesn't stretch no nonsense. Not sure exactly where my post failed to stretch no nonsense.... |
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Post by dappy on Oct 3, 2023 11:38:07 GMT
So add a 20 mph speed limit on that, it will 'slow you down' even more. Ok let's go over it.
Assuming when you approach 'traffic lights' and 'pedestrian crossings' and of course 'congestion', that tend to 'slow you down', you will be doing (hopefully) 20 mph or less in these scenarios, so you have basically just admitted that 20 mph zones cause congestion.
Not sure exactly where my post failed to stretch no nonsense.... Second post in a row when I genuinely have no idea what on earth you are talking about. Are you OK? |
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Post by Deleted on Oct 3, 2023 12:21:51 GMT
Slower speeds save lives.
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Post by jonksy on Oct 3, 2023 12:23:41 GMT
Not sure the relevance of 40mph to the discussion Dan? Well of course you didn't. |
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Post by buccaneer on Oct 3, 2023 12:32:06 GMT
I take it you too can’t think of any downsides to reducing the speed limit to 20 from 30? You have had plenty of opportunity but have so far come up with nothing. It’s a fair question to ask what the benefits are and we should move on to that. We have had a good couple of hours and so far nothing (apart from Steppens personal skill limitations). Are there any or do we simply accept that there are none. I see you've avoided my question. Perhaps it's because you don't have any reason to stand behind the sudden reduced speed limit. |
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Post by The Squeezed Middle on Oct 3, 2023 13:13:39 GMT
Ah, the Graun.
LOL!
Meanwhile, here's a couple of other pieces of research showing that fuel economy drops off markedly below 30mph.
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Post by Fairsociety on Oct 3, 2023 13:19:18 GMT
Not sure I understand your point Pacifico. The question I posed was “what are the downsides in reducing the standard speed limit in a medium sized city from 30mph to 20mph.” You don’t seem to have answered the question. I haven’t really thought about it before. Until Sunak made it a national issue it felt like a matter for locally elected councillors to decide for their patch. But as it’s now a national political issue I thought I ought to consider it. And frankly I can’t think of much of a downside. I am prepared to listen as I am trying to work out my view but the only reason to keep it at 30 so far is that one driver is apparently unable to control his vehicle which isn’t overly convincing….. That runs throughout all your posts. |
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Post by dappy on Oct 3, 2023 14:12:38 GMT
Ah, the Graun.
LOL!
Meanwhile, here's a couple of other pieces of research showing that fuel economy drops off markedly below 30mph.
You are confusing emissions that will be made in a hypothetical world of constant 20mph and constant 30mph (for most cars 30mph will be less) with real world emissions in an urban landscape where vehicles are constantly accelerating and breaking. Emissions peak during acceleration and hence where vehicles are regularly accelerating from 0 to 30 and then back to 0 emissions will be higher than when accelerating from 0-20. Of course in many real world scenarios the vehicles will never get up to 20mph at all - in which case there is no advantage or harm in reducing the speed limit |
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Post by The Squeezed Middle on Oct 3, 2023 14:27:40 GMT
Ah yes, Dippy's hypothetical world. But I'm thinking of my real world where some of the major roads on my route to work have been reduced, quite unnecessarily, to 20mph causing vehicles to grind along in second gear instead of loping along at constant speed, at much lower revs, in third.
Similar is reported by my colleagues. The simple fact is that while electric vehicles are happy at any speed, ICE vehicles are simply not designed to maintain 20mph and are neither happy nor economical doing so.
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Post by dappy on Oct 3, 2023 14:38:21 GMT
Ok lets summarise where we have got to Challenged with identifying the downsides of reducing the speed limit for urban roads from 30 to 20, we have over several hours been offered the following reasons 1) pollution - actually the data seems to show that in most cases of stop start traffic , the actual outcome is less not more pollution 2) travel times - travel distances in 30mpg areas tend to be quite short (at most 3-5 miles) and by their nature journeys are likely to be a degree of stop start. As such basic maths says that difference in travel tim e between a 20mpg zone and a 30mpg zone is .likely to be minimal - 1-2 minutes at most. 3) not being a competent driver - surely irrelevant 4) something unintelligible to do with bus lanes. So frankly not much. So now lets turn to the benefits 1) the pollution issue outlined as a negative is in practice a positive 2) road safety - the data is not definitive but seems to suggest that at worst this is neutral, at best there are significant savings of life and serious injury. blogs.napier.ac.uk/tri/technical-papers/3) A feeling of safety - giving cyclists and pedestrians a greater feeling of safety and hence promoting their use rather than car use with obvious health and pollution benefits. So what to conclude? It feels like the choice is broadly between sticking with 30mph, saving one minute travel time at the expense of killing more children or moving towards a 20mph limit on most (but not necessarily all) existing 30mph areas. Interesting to work through the arguments reaching a conclusion that I didn't really expect to at the start of the conversation. |
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