Wales 20mph limit starts Sept 17th - a heads-up

[Bigshug]

I was taught that 30 mph was 45feet per second

 

[Norfolk NewBoy]

I was taught that 30 mph was 45feet per second

CORRECT! I meant 15 yards per second (doing the maths while in bed )

Gordon

 

[Rolyan57]

A

You are CORRECT: the data is not available!
Your 15 mile journey at 30mph would take you 30 minutes.
Your 15 mile journey at 20mph would take you 45 minutes.
IF you feel that your 15 minutes is more important than any lives which might potentially be lost then that is your opinion, and you have justified your choice by referring to society balancing speed against transport requirements.
HOWEVER, you admit to your average being less than 30mph so are you prepared to share typical journey times (average speeds)? Personally, I would be interested to know where your commute occurs, as a 15 mile urban trip without traffic lights, roundabouts, etc whilst remaining in a 30mph limit is intriguing.

Checking back through my posts I cannot see where I have stated that journey times WOULD not increase, simply that they wouldn't increase by 50% because of other driving constraints. I even hope that times will not increase noticeably because when vehicles travel at similar speeds there is less speeding up and slowing down.
Here is an example: to drive to my daughter's house I have to turn right from a moderately-busy main road into her housing estate. 10-20% of the time I'm able to swing in without stopping but in most cases I have to come to a halt AND so do any vehicles behind me. I sit there (and so do they) until I spot a large enough gap or someone signals me to cross in front of them: typically this might be 30seconds.

I estimate that. from a standing start, it is going to take me 2 seconds to reach safety.
30mph is approximately 15 feet per second so I need a gap of 30 feet.
20mph is 10 fps, so a gap of 20 feet will suffice.

I don't know if vehicles will maintain current gaps, making it more likely that I'll get across with a shorter delay OR if cars travelling at 20mph will be more prepared to allow me over. However, I hope that a gentler pace of driving will engender greater consideration for other people, although I suspect that some folk who are regretting all their lost minutes might be more aggressive. Also, obviously, slower vehicles may drive closer together, so large gaps would be less frequent. We don't have the data so it's all conjecture.

Gordon

As you say, you don’t have the data.

However, on my journeys, restricting roads to 20mph from 30mph would mean the journeys would take considerably longer.

Each person and situation is different.

 

[Norfolk NewBoy]

A

As you say, you don’t have the data.

However, on my journeys, restricting roads to 20mph from 30mph would mean the journeys would take considerably longer.

Each person and situation is different.

Why don't you share the data for your daily commute, as it currently stands?
You state it is 15 miles and you average just under 30mph but WHERE and WHEN do you do this?

Gordon

 

[Glandwr]

When I last saw the average speed of journeys in UK metropolitan areas I can't remember a single one more than 20mph

 

[Rolyan57]

Why don't you share the data for your daily commute, as it currently stands?
You state it is 15 miles and you average just under 30mph but WHERE and WHEN do you do this?

Gordon

My daily commute was about 15 miles. For a large part of that the traffic moved at a relatively steady 30mph. If it was reduced to 20 mph it would take longer.

As I’ve said before there are pros and cons. But it’s ridiculous to suggest that it won’t take longer. It will.

I’m entitled to that opinion, just as others are entitled to a different one.

 

[Glandwr]

My daily commute was about 15 miles. For a large part of that the traffic moved at a relatively steady 30mph. If it was reduced to 20 mph it would take longer.

As I’ve said before there are pros and cons. But it’s ridiculous to suggest that it won’t take longer. It will.

I’m entitled to that opinion, just as others are entitled to a different one.

Of course you are. Just trying to understand what you are saying. Are your saying that the journey is 15 miles along 30 mph roads and that you manage a steady 30 mph or .....

 

[Rolyan57]

Of course you are. Just trying to understand what you are saying. Are your saying that the journey is 15 miles along 30 mph roads and that you manage a steady 30 mph or .....

The journey is about 15 miles. Almost all of that is 30mph zone. The traffic is relatively free moving. My average will be less than 30mph. If they were all 20mph zones, my average would be less than 20mph.

 

[GMJ]

...and if a child ran out into the road hopefully you would have the satisfaction of being able to avoid killing them, if you struck them. That would make the extra few minutes on the journey worthwhile I would guess.

 

[ricc]

30 mile journey at 30 mph takes an hour , at 20 it takes an hour and a half therefore at any one time there will be 50 percent more cars on the roads in urban areas making more traffic Jams and even lower overallll speeds. Engines will be running longer in lower gears hence even more pollllution and lower air quality ergo more deaths from respiratory diseases.

 

[Glandwr]

True in theory but In practice the average observed in our large towns and cities now is well below 20mph. Junctions, pedestrian crossings, traffic lights, give way signs, defensive driving manoeuvring not to mention speed dictated by the driver in front determine our progress as much or more than the speed limit.

Dropping the speed limit by 10mph does not result in 10mph slower journeys any more than increasing it by 10 would result in 10mph faster journeys.

 

[Norfolk NewBoy]

On local BBC News last night was a report that residents in Swaffham, 10 miles from me, are asking for the 20mph zone in the town centre to be extended to the entire town. They believe that it will help drivers to stick to the speed limit and cause less congestion when cars slow down for traffic lights, road junctions, circumnavigating parked vehicles, etc. Apparently there are 50 towns and villages in Suffolk asking for similar restrictions.

Gordon

 

[Robmac]

On local BBC News last night was a report that residents in Swaffham, 10 miles from me, are asking for the 20mph zone in the town centre to be extended to the entire town. They believe that it will help drivers to stick to the speed limit and cause less congestion when cars slow down for traffic lights, road junctions, circumnavigating parked vehicles, etc. Apparently there are 50 towns and villages in Suffolk asking for similar restrictions.

Gordon

Unfortunately, drivers willing to ignore a 30 mph limit will probably still ignore a 20 limit.

 

[colinm]

30 mile journey at 30 mph takes an hour , at 20 it takes an hour and a half therefore at any one time there will be 50 percent more cars on the roads in urban areas making more traffic Jams and even lower overallll speeds. Engines will be running longer in lower gears hence even more pollllution and lower air quality ergo more deaths from respiratory diseases.

That's your opinion. Now lets post the facts.
Yes there may be an increase in travel time, but it will not be 1/2 hour longer because it's very unlikely you can maintain 30mph for an hour in a 30 limit.
There will not be more traffic jams in roads due to 20mph limit.
Only one study has shown a increase in polution due to lower limits, and this was due to speed bumps causing traffic to slow down then speed up.

 

[Glandwr]

Let's face it reason has little to do with it. The 20mph law has moved into a wedge political issue. When the issue was first proposed in Wales it had almost universal support across the parties. Now since the infamous ULEZ byelectipn in the early summer one politic party in Wales is now actively against the "bonkers" decision

 

[Rolyan57]

...and if a child ran out into the road hopefully you would have the satisfaction of being able to avoid killing them, if you struck them. That would make the extra few minutes on the journey worthwhile I would guess.

What’s the minimum speed you would accept on all roads throughout the U.K., bearing in mind that if a child ran out on one of them you might avoid hitting them.

15mph urban. 10mph. How about 40mph on rural. 30mph. How about 10mph in all city streets.

All of which ignores the fact that reasonable debate involves looking at all the pros and cons. The disagreement comes when some try to misrepresent things by claiming journey times won’t change.

 

[Rolyan57]

That's your opinion. Now lets post the facts.
Yes there may be an increase in travel time, but it will not be 1/2 hour longer because it's very unlikely you can maintain 30mph for an hour in a 30 limit.
There will not be more traffic jams in roads due to 20mph limit.
Only one study has shown an increase in polution due to lower limits, and this was due to speed bumps causing traffic to slow down then speed up.

At least you’ve acknowledged that there will be an increase in journey times. Some try to claim there won’t be

One study out of how many? That’s important. Plus what were the circumstances? That’s also very important. Without that info you can’t draw conclusions from that study and relate it to this blanket ban.

Near me, the only 20 zones that are successful are the ones with speed calming measures such as speed bumps. So assuming those are rolled out, there may well be an increase in pollution.

This is clearly not as black and white as some would like to suggest.

 

[colinm]

At least you’ve acknowledged that there will be an increase in journey times. Some try to claim there won’t be

One study out of how many? That’s important. Plus what were the circumstances? That’s also very important. Without that info you can’t draw conclusions from that study and relate it to this blanket ban.

Near me, the only 20 zones that are successful are the ones with speed calming measures such as speed bumps. So assuming those are rolled out, there may well be an increase in pollution.

This is clearly not as black and white as some would like to suggest.

I can't be bothered ATM to trawl back through my internet history to give a definitive answer, but there have been several studies which have looked into the effects of 20mph limits, all but one have shown that emissions decrease, the one that showed an increase was not due to the 20mph limit, but due to it using speed bumps, this also applies to 30mph limits. 20mph limits have been in the towns, and now some villages, around where I live for around 20 years, interestingly most of these don't use speed bumps, but they are often used in some 30mph limits, in fact from memory the speed bumps that are in 20mph limits where actually built when they where still 30mph limits.
You 'assume' that speed bumps will be introduced in 20mph limits, yet when I drove in the 20mph limit in Cardiff which has been there for some time I don't recall any speed bumps, and I've 'travelled' the route just now on google into central Cardiff and sure enough there are no speed bumps.

 

[Rolyan57]

I can't be bothered ATM to trawl back through my internet history to give a definitive answer, but there have been several studies which have looked into the effects of 20mph limits, all but one have shown that emissions decrease, the one that showed an increase was not due to the 20mph limit, but due to it using speed bumps, this also applies to 30mph limits. 20mph limits have been in the towns, and now some villages, around where I live for around 20 years, interestingly most of these don't use speed bumps, but they are often used in some 30mph limits, in fact from memory the speed bumps that are in 20mph limits where actually built when they where still 30mph limits.
You 'assume' that speed bumps will be introduced in 20mph limits, yet when I drove in the 20mph limit in Cardiff which has been there for some time I don't recall any speed bumps, and I've 'travelled' the route just now on google into central Cardiff and sure enough there are no speed bumps.

Sadly without much more detailed information on the studies you refer to, we cannot tell if the results are applicable to this.

I said “assuming that speed bumps are used” because in my experience around my area (and other travels) 20mph limits are not upheld where people feel they’re not appropriate. That will be the case with a blanket introduction. The only way to enforce them is speed bumps and enforcement, and even then a large percentage of modern cars ignore them. In those around me I can confidently state that almost no one obeys the limit.

The idea that motorists will suddenly follow all 20mph limits (without considerable road changes and major expense on enforcement) is as ridiculous as the idea that journey times won’t increase.

 

[colinm]

Sadly without much more detailed information on the studies you refer to, we cannot tell if the results are applicable to this.

I said “assuming that speed bumps are used” because in my experience around my area (and other travels) 20mph limits are not upheld where people feel they’re not appropriate. That will be the case with a blanket introduction. The only way to enforce them is speed bumps and enforcement, and even then a large percentage of modern cars ignore them. In those around me I can confidently state that almost no one obeys the limit.

The idea that motorists will suddenly follow all 20mph limits (without considerable road changes and major expense on enforcement) is as ridiculous as the idea that journey times won’t increase.