20mph residential speed limit (replacing 30mph)

ICDP said:
I was showing deliberately conflicting data that claimed the emissions would be reduced. And another that showed results were conflicted.

My claim is that emissions overall will not be a major factor either way and is a straw man. I was countering the anecdotal claims that emissions would much worse at slower speeds.

So if pollution and emissions is not a major factor then that leaves us with a reduction in road fatalities and a reduction in collisions. I’m sorry but to me both trump the fact that some ignorant impatient moron wants to drive a bit faster.
Click to expand...

These limits are often sold as having environmental benefits - few studies, especially with modern vehicles and traffic patterns, show that to be true, varying from "no net negative impact" to having moderate negative impact. Rarely are potentially quite negative aspects taken into account such as the real world impact on the lifespan and efficiency of car components like DPF, EGR, catalytic converters and turbos, etc. when they spend more time operating below optimal temperatures - which itself will have both an economical and environmental impact both from needing to be replaced more often and working less effectively. (Or as above where even a small increase in pollution can potentially result in more deaths than those saved from collisions).

20 limits can have an impact on reducing collisions and fatalities but despite what some are trying to sell, often using the % chance of serious injury in a collision 20 vs 30 etc., in the real world it is more complicated than that - you can't just slap 20 limits all over and get those benefits - for example in some layouts involving narrow streets with a lot of parked cars such as is the case in some cities/districts in the UK 20 limits have substantially reduced incidents, but in other cases will have no significant impact at all. (EDIT: Also the risk as I mentioned before if these limits aren't used judiciously of eroding the effectiveness of those limits in areas where they are more crucial).

There is an extensive study done by Birmingham https://www.birmingham.gov.uk/download/downloads/id/23868/20mph_areas_monitoring_report.pdf but their outcomes have been distorted by the reduction in traffic volumes due to COVID and lockdowns so it isn't a very reliable study in that respect for some things but also mentions studies in other areas - which are a more varied story - some of those reported reduction in numbers after the first year but if you dig up the data for the years around that it is within the normal year on year fluctuations.

EDIT: PS I'm happy to upload hours and hours of footage showing I'm generally not an impatient driver, make time for other road users where I can and stick to the speed limits in residential areas and 30s and 40s :s even out of town 40s in the middle of the night I stick to 40 personally when many will happily do far faster.
 
Last edited:
ICDP said:
Just using MPG is extremely simplistic and will vary from car to car.

Click to expand...

I've currently got 5 cars myself & access to about another 20, shall we give them all a go?

There are a mixture of fuel types & every transmission type other than CVT (Who would want one of those though? Yuck)
 
Iamzod said:
I've currently got 5 cars myself & access to about another 20, shall we give them all a go?

There are a mixture of fuel types & every transmission type other than CVT (Who would want one of those though? Yuck)
Click to expand...

I have one vehicle with CVT, would not recommend - on hills it can be a little tricky keeping to a constant speed and it sits far more happily at 30 than 20. The one I have doesn't really have a problem with lag/elastic band response and you kind of quickly learn how to compensate for that though, but it does make an unpleasant droning/whine though to be fair you can just drown that out with a bit of music.

Something I see brought up a bit with regard to emissions is that hope that the reduced limits will encourage more people to use other, less polluting, forms of transport but personally don't believe that really will work to any significant level - by far the larger number of people driving on the roads are there not by choice whether driving for business reasons, driving to work because it is the only really practical method for them or whatever and especially in more built up areas people will be far more likely using other modes of transport if they can over a car for short journeys. What some people don't seem to understand is that the modern way of life has pushed a lot of people to the car who don't even necessarily want to be driving and even with more sections of 20 limits, etc. many people trying to cycle will still need to navigate higher speed roads which often these days are nigh on suicidal and that risk would have to come down before people would turn to cycling in mass so chicken and egg situation.

And interesting twist on that - places where 20 limits have encouraged a larger number to start cycling have consequently seen the number of incidents involving cyclists increase (such as Brighton and Hove) substantially. Interestingly despite a first year reduction in accidents in the Brighton and Hove districts with 20 MPH limits introduced (though those numbers are within margin of error for previous years) they've mysteriously not updated the studies in subsequent years when it has increased year on year and now far above the 2013-14 numbers :s a similar story exists for many of the other studies I've Googled where the first 1-3 years saw figures showing a slight reduction, but usually still inline with the fluctuation in previous years, then they've stopped updating the studies after the figures went the other way.

EDIT: Hard to get focussed figures for just the 20MPH areas for a larger range of years but the 20 MPH limits haven't had much effect on the overall road deaths for the area including the 20MPH zones and surrounding areas:

Code: 
2005    55 (34%)    21 (13%)    39 (24%)    40 (25%)    6 (4%)    161 (100%)
2006    61 (36%)    28 (16%)    41 (24%)    34 (20%)    7 (4%)    171 (100%)
2007    62 (38%)    23 (14%)    37 (23%)    32 (20%)    10 (6%)    164 (100%)
2008    46 (33%)    22 (16%)    35 (25%)    30 (21%)    8 (6%)    141 (100%)
2009    58 (39%)    32 (21%)    32 (21%)    19 (13%)    9 (6%)    150 (100%)
2010    48 (35%)    23 (17%)    37 (27%)    26 (19%)    2 (1%)    136 (100%)
2011    62 (36%)    35 (20%)    43 (25%)    22 (13%)    10 (6%)    172 (100%)
2012    54 (34%)    35 (22%)    35 (22%)    25 (16%)    11 (7%)    160 (100%)

2013    47 (32%)    36 (25%)    17 (12%)    39 (27%)    6 (4%)    145 (100%)

2014    44 (28%)    46 (29%)    25 (16%)    36 (23%)    7 (4%)    158 (100%)
2015    40 (26%)    44 (29%)    33 (22%)    24 (16%)    11 (7%)    152 (100%)
2016    58 (34%)    49 (29%)    27 (16%)    31 (18%)    4 (2%)    169 (100%)
2017    51 (32%)    47 (30%)    34 (22%)    21 (13%)    5 (3%)    158 (100%)
2018    47 (28%)    47 (28%)    41 (25%)    26 (16%)    4 (2%)    165 (100%)

(First column after the year is pedestrians, second is cyclists, last one is total deaths).

There was a small, but within normal fluctuation, decrease in 2013 after the introduction of the 20 MPH zones, but then a significant increase in number of cyclist deaths attributed to a subsequent increase in the number of people cycling. Whether more widespread 20s and/or decreasing other limits would have an impact is another story again but I'm not personally convinced it will have the effect people are claiming.
 
Last edited:
413x said:
How many drivers are going to want to sit at 15mph waiting for a space, often no space, to overtake Vs trying a dodgy overtake.
Click to expand...
ban over taking on residential streets that have no space for it and then problem solved, alternatively put speed bumps on every road
 
Last edited:
Rroff said:
These limits are often sold as having environmental benefits - few studies, especially with modern vehicles and traffic patterns, show that to be true, varying from "no net negative impact" to having moderate negative impact. Rarely are potentially quite negative aspects taken into account such as the real world impact on the lifespan and efficiency of car components like DPF, EGR, catalytic converters and turbos, etc. when they spend more time operating below optimal temperatures - which itself will have both an economical and environmental impact both from needing to be replaced more often and working less effectively. (Or as above where even a small increase in pollution can potentially result in more deaths than those saved from collisions).

20 limits can have an impact on reducing collisions and fatalities but despite what some are trying to sell, often using the % chance of serious injury in a collision 20 vs 30 etc., in the real world it is more complicated than that - you can't just slap 20 limits all over and get those benefits - for example in some layouts involving narrow streets with a lot of parked cars such as is the case in some cities/districts in the UK 20 limits have substantially reduced incidents, but in other cases will have no significant impact at all. (EDIT: Also the risk as I mentioned before if these limits aren't used judiciously of eroding the effectiveness of those limits in areas where they are more crucial).

There is an extensive study done by Birmingham https://www.birmingham.gov.uk/download/downloads/id/23868/20mph_areas_monitoring_report.pdf but their outcomes have been distorted by the reduction in traffic volumes due to COVID and lockdowns so it isn't a very reliable study in that respect for some things but also mentions studies in other areas - which are a more varied story - some of those reported reduction in numbers after the first year but if you dig up the data for the years around that it is within the normal year on year fluctuations.

EDIT: PS I'm happy to upload hours and hours of footage showing I'm generally not an impatient driver, make time for other road users where I can and stick to the speed limits in residential areas and 30s and 40s :s even out of town 40s in the middle of the night I stick to 40 personally when many will happily do far faster.
Click to expand...

I know what you mean and that’s why I tried to compare various studies. It is also why I deliberately ignored some of the obviously biased reports from 20isPlenty for example. Similarly I can easily find articles from petrol head sites that show significant increase in pollution but funnily enough they never link their sources (a red flag to me). Covid lockdowns have also skewed results in places such as Edinburgh, though their data suggests a slight reduction post Covid as well. I wonder how much is down to a significant percentage of people who stayed working from home?

The indications are from reasonably independent sources that there is no significant difference in pollution either way. Though I stress once again this is a red herring, because the kind of people moaning about pollution are not exactly known for their anti pollution stance. The reason this new limit was brought in has been stated as reducing road related injuries and fatalities and even reports in that are mixed.
 
Rroff said:
And interesting twist on that - places where 20 limits have encouraged a larger number to start cycling have consequently seen the number of incidents involving cyclists increase (such as Brighton and Hove) substantially. Interestingly despite a first year reduction in accidents in the Brighton and Hove districts with 20 MPH limits introduced (though those numbers are within margin of error for previous years) they've mysteriously not updated the studies in subsequent years when it has increased year on year and now far above the 2013-14 numbers :s a similar story exists for many of the other studies I've Googled where the first 1-3 years saw figures showing a slight reduction, but usually still inline with the fluctuation in previous years, then they've stopped updating the studies after the figures went the other way
Click to expand...
more people cycling, because of better road cycling environment, improved their overall health, so their overall mortality rate reduced, but,
those new cyclists did have an increased propensity for bicycle accidents, due to inexperience ?
 
jpaul said:
more people cycling, because of better road cycling environment, improved their overall health, so their overall mortality rate reduced, but,
those new cyclists did have an increased propensity for bicycle accidents, due to inexperience ?
Click to expand...

Would be interesting, though nigh impossible, to know how that balances out.

I'd assume inexperience plays a role here. At least around where I live/work the roads are lethal for cyclists even in lower speed traffic.
 
Last edited:
some data on cycling experience vs incidents
LOL the terminology is well chosen ... yes I'd say I have 2 incidents a day, and a very scary incident once a week, as an 11+


53233895967_60592d346e_o_d.jpg


e: 8 mile daily - one incident bmw 4 series <2ft pass 30mph town -
like many drivers unable to compute relative speed of 3 vehicles & modulate speed such that he didn't arrive adjacent to me at same time as someone coming towards us.
 
Last edited:
So it's been over a month now and before it all came in i was between neutral and slightly in favour of the new limits, Since i've had to live with it though i've definitely changed my mind to being very against it.

Luckily almost everyone just ignores it completely but when you do have to do 20 for miles of road it's pretty soul crushing, it'd take me an extra 10 minutes to get to work now if i actually did 20 where i'm meant to.

The main thing i've got against it is how much conflict it's introduced on the roads, there's a minority of people who actually do 20 but it's causing so much grief from the again opposite minority who will then tailgate and overtake.

I don't understand the argument to 'get people out of cars' as there's no other alternative where i live, they're cutting the already woeful bus services even more so they're less frequent and go to even less places, it's too hilly to cycle (not that i'm well enough to do that anyway) and there's 0 cycling infrastructure anyway so i don't know what they want other than to frustrate everyone?
 
Did look to see if this has been covered but my searching is rubbish.

Had to go to Wrexham yesterday and came upon my first 20mph speed limit -Seems whole of Wrexham is 20.
Have to say it did seem much safer to drive and you have more of a chance at hearing and obeying sat nav. Also what a PITA doing 20.
Having cruise control was a boon.

I dodged out back onto Oswestry road to come back home on. Won't be going there again.
 
Not meaning to be funny but if you turn on cruise control at 20mph then it's actually less safe as you're less likely to respond as quickly if someone steps out. But yes it is a pain doing 20 for miles.
 
Hades said:
Not meaning to be funny but if you turn on cruise control at 20mph then it's actually less safe as you're less likely to respond as quickly if someone steps out. But yes it is a pain doing 20 for miles.
Click to expand...
Why are you less likely to respond quickly? With CC on you can already have your foot ready to use the brake and you can be more focused on the road then then speedo?
 
In various areas near me, very few folk actually stick to 20mph in these areas. The number of times I've been driving back into my village at 20mph (the road into the village goes from a 40mph to a 20mph and goes past a school, a kids park and a care home) and then looked in my mirror to see some absolute tool zooming up behind me at @40mph then tailgating me is a regular occurrence :rolleyes:

These types (on this road near me at least) also seem to have no mechanical sympathy - the entire road is full of quite severe speed bumps and again, looking in your rear view mirror you can see these idiots bouncing over them at silly speeds. Goodness knows how bone rattling for their suspension components it must be!!
 
I drove back from the M3 to SE London (Eltham) on Wednesday and for about 2 hours I was crawling in traffic along the South Circular at a maximum of 20mph. It was painful for such a major route to be so slow now. There is one point that opens up into a dual carriageway for a little bit that is 40 still and it felt so fast for the 10 seconds I was on that bit of road lol
 
I live in a town now that has a 20Mph limit.

It starts up a steep hill (8.2% gradient) which leads to the town centre and continues through most of the town. No issues with it really.
 
Syla5 said:
Why are you less likely to respond quickly? With CC on you can already have your foot ready to use the brake and you can be more focused on the road then then speedo?
Click to expand...
My opinion is that you are more attentive while in full control of the car (foot on one of the pedals). Also if you do hit someone or something unexpectedly then the accelerator is still "on" with cruise control. But if you have to put your foot on the accelerator to actually move forward then your foot is more likely to come off the pedal in an unexpected accident.
 
Last edited:
I would be surprised if any car with cruise control doesn't have automatic responses to collisions. All the cars I've drive with CC will react to braking for example, also your example is flawed again in that if you hit someone while you have your foot on the accelerator you have to factor in reaction time to remove your foot from the accelerator and move it to the brake pedal. People also suffer from pedal panic as well and when they are doing something wrong many react by pressing what they already have their foot on as that's a quicker more knee jerk reaction then lifting / moving / pressing.

Also those people who don't pay attention while using cruise control aren't going to pay attention if not! Using cruise control you often realise just how many people are completely oblivious to their own speed, especially so on motorways and areas that change from 20/30/40 multiple times over short distances.
 
Last edited:
DXP55 said:
Did look to see if this has been covered but my searching is rubbish.
Click to expand...

20mph residential speed limit (replacing 30mph)

So this is a hit topic this side of the border. Mainly affecting south Wales I think. But other areas too. From (next week?) we have been told to assume where 30 was is now 20..unless told otherwise. This is being done under for safety. My opinion.. I'm against this myself. A few...
forums.overclockers.co.uk forums.overclockers.co.uk
 
You must log in or register to reply here.
Back
Top Bottom