Netherlands reduces speed limit to 100 km/h in daytime

bramling · 13 Nov 2019

DerekC said:
Building up momentum on downhills and not maintaining high speed up hills is good practice, but what wastes energy is braking - so taking your foot off the loud pedal early is highly recommended. And it's simply untrue to say that "the difference in fuel economy between 85mph and 60 mph is fairly minimal". At high speeds aerodynamic drag predominates and that increases in proportion to speed if your car is highly aerodynamic so that laminar flow is maintained - worse if it isn't. You can expect to use somewhere around 40% more fuel at 85mph than 60mph - and that's borne out pretty accurately by the charts posted above (post#9). What tends to mask this stark difference, I think, is that it's actually quite hard to drive at a steady 60mph - you are continually being overtaken by trucks, having to get out of the way of joining traffic at on-slips etc etc, so in reality speed varies a lot and tends to edge upwards (at least, mine does).

Simply going my the data my car provides for the journey in question, at 60 mph the car will average around 36 mpg, whereas running at 85 mph for the motorway section (around 10 miles) the figure will only come down to about 34.5 mpg with a cold start or slightly better in summer.

This is of course at a time when the road is fairly clear, it all pales into insignificance on something like midday on Sunday in the run up to Christmas when congestion will pull things down to as low as 29 mpg. In that situation I’d suggest any reduction in top speed on the motorway would make little if any difference to the final figure.

As an aside I tend to drive with at least the driver’s window fully down most of the time, and quite often the passenger window too. No doubt I could claw back a bit of economy by not doing that. By contrast I rarely if ever use the air conditioning.

Were a lower speed to be enforced on the motorway, in practice I’d almost certainly be tempted to come off at an earlier junction and do the last 10 miles on an adjacent B-road, which would involve considerable speeding up and slowing down in order to match the safe speed profile of the road through its many blind corners. I’m not sure that’s an ideal consequence just to save a couple of drops of petrol.

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AM9 · 13 Nov 2019

bramling said:
Using that logic one could argue that a car at 55 mph is inferior to one at 0 mph! ...

Pointless argument, - a car travelling at 0mph won't be getting anywhere unless you are advocating not using a car.
Irrespective of whether the "fuel-efficient practices" are used, travel at 55 mph uses more fuel than at 70mph or 80mph. Fuel used is proportional to air resistance which is proportional to the square of the speed depending on gearing and engine power curve efficiency, so just holding 80mph uses more fuel as DerekC says, however 'smart' the driver is.

Bald Rick · 13 Nov 2019

bramling said:
Just going on fuel economy I can drive from Hertfordshire to outer London via the A1, and with a clear road the difference in fuel economy between 85 mph and 60 mph is fairly minimal.

“At this point the Hertfordshire Constabulary had seen enough...”

Bevan Price · 13 Nov 2019

bramling said:
A lot more pollution could be avoided by teaching drivers how to drive efficiently (in other words maintaining a constant speed instead of slowing down and speeding up unnecessarily), and clamping down on poorly maintained vehicles.

A situation not helped by the proliferation of speed humps, raised junctions, etc., where you get some people slowing to 5-10 mph, then accelerating towards the next hump. Has anyone tested air pollution on roads afflicted with speed humps? - I bet it is a lot worse than on "hump-free" roads.

Bald Rick · 13 Nov 2019

Bletchleyite said:
We kind of have done. Smart motorways with cameras have reduced the prevailing speed on UK motorways from around 80-90mph to around 70mph, at least on those stretches but I've noticed it on others too.

Agreed. In the South East, the M40 and A1(M) are just about the only motorways now where you will see people cruising at 80mph+.

bramling said:
Simply going my the data my car provides for the journey in question, at 60 mph the car will average around 36 mpg, whereas running at 85 mph for the motorway section (around 10 miles) the figure will only come down to about 34.5 mpg with a cold start or slightly better in summer.

If I were you I’d consider a different car. In my almost 10 year old Golf I would average 50+ mpg for a journey of around 20 miles with half of it cruising at 60mph on the motorway. I recently did a 70mile return trip to MK, of which 55 miles was on the M1, and averaged 72mpg.

Bald Rick · 13 Nov 2019

Bevan Price said:
A situation not helped by the proliferation of speed humps, raised junctions, etc., where you get some people slowing to 5-10 mph, then accelerating towards the next hump. Has anyone tested air pollution on roads afflicted with speed humps? - I bet it is a lot worse than on "hump-free" roads.

There has been research, and yes pollution is worse. As is car repair bills (tyres, suspension etc). However fewer dead children, which I think is the right answer.

bramling · 13 Nov 2019

Bald Rick said:
There has been research, and yes pollution is worse. As is car repair bills (tyres, suspension etc). However fewer dead children, which I think is the right answer.

But will children suffer in the longer term from constantly getting mouthfuls of exhaust? Near me there’s a road with speed humps, the road having a modest gradient. For me walking to town involves crossing this road, and it’s inevitably the case that there will be vehicles passing at the point I arrive to cross. Every vehicle will deposit a mouthful of fumes as it accelerates away from the hump. Personally I’d rather not have them.

Bald Rick · 13 Nov 2019

bramling said:
But will children suffer in the longer term from constantly getting mouthfuls of exhaust?

Possibly, but I’d argue it’s better for them to have a longer term, than not.

bramling · 13 Nov 2019

Bald Rick said:
Agreed. In the South East, the M40 and A1(M) are just about the only motorways now where you will see people cruising at 80mph+.

If I were you I’d consider a different car. In my almost 10 year old Golf I would average 50+ mpg for a journey of around 20 miles with half of it cruising at 60mph on the motorway. I recently did a 70mile return trip to MK, of which 55 miles was on the M1, and averaged 72mpg.

At the end of the day I don’t do enough miles to be too bothered. If I used the car daily (as may well be the case in the not-too-distant future) then I probably would get something smaller. However as it is one of my cars rarely moves more than once a month (except for summer holidays) and the other doesn’t do a massive amount at this time of year bar sporadic runs to London and the odd local trip.

Ironically the biggest factors which have increased my car mileage have been (1) the increased unreliability of weekend rail services in the last 5 or so years, (2) weekend rail services having become noticeably more crowded to the point where I find them unpleasant to use, and (3) the arrival of the class 700s, although fortunately I’m able to avoid them 99% of the time.

Im happy to take the hit with running a larger car to London once in a while.

As regards cruising at 80+ mph, don’t forget the non-motorway section of the A1, which I find an increasingly attractive alternative to the M1. For getting to the north-west at present I would tend to do A1, A14, M1 and thence across to Stoke-on-Trent finally joining the M6 at Crewe.

eMeS · 14 Nov 2019

Lucan said:
They could do a lot to reduce pollution, in cities at least, by getting some competent people to program traffic lights. ...

Several traffic-light assisted roundabouts in central Milton Keynes seem to have had their traffic-lights switched off (& labelled with a large, narrow "X"). It's not clear whether this is an experiment, or permanent. The labelling isn't that clear the first time you come across them. Traffic flow doesn't seem to be any worse, but then I'm no longer a commuter.

cactustwirly · 14 Nov 2019

Bald Rick said:
Agreed. In the South East, the M40 and A1(M) are just about the only motorways now where you will see people cruising at 80mph+.

If I were you I’d consider a different car. In my almost 10 year old Golf I would average 50+ mpg for a journey of around 20 miles with half of it cruising at 60mph on the motorway. I recently did a 70mile return trip to MK, of which 55 miles was on the M1, and averaged 72mpg.

Plus the M4, M3, M20 etc

TRAX · 14 Nov 2019

GRALISTAIR said:
Slightly hyperbolic but I do agree that we concentrate too much on small cars and not enough on short range Boeing 737/Airbus 320 series etc. A 777 across the Atlantic sure puts out some carbon footprint. Huge trucks in the UK do too.

When you take into account the fuel consumption per passenger-km of a transatlantic 777 flight, the carbon footprint of that plane is tiny.
This plane-shaming business is ridiculous. And how would you travel to America if not by plane ? Electric bike ? :lol:

radamfi · 14 Nov 2019

People on this thread have been talking a lot about fuel consumption, but this is about emissions.

See figures 3 and 4 in

https://www.eea.europa.eu/themes/transport/speed-limits-fuel-consumption-and/speed-limits

For diesels, there is a 40% increase in NOx at 120 km/h compared to 100 km/h.

For petrol, there is a 60% increase in CO at 110 km/h compared to 100 km/h. NOx is actually lower at that speed, but petrol cars emit a lot less NOx compared to diesel, so reducing the limit to 100 km/h is better overall.

Of course, this is Euro 4, so older cars, but there are a lot of older cars still running.

edwin_m · 14 Nov 2019

bramling said:
But will children suffer in the longer term from constantly getting mouthfuls of exhaust? Near me there’s a road with speed humps, the road having a modest gradient. For me walking to town involves crossing this road, and it’s inevitably the case that there will be vehicles passing at the point I arrive to cross. Every vehicle will deposit a mouthful of fumes as it accelerates away from the hump. Personally I’d rather not have them.

Bald Rick said:
Possibly, but I’d argue it’s better for them to have a longer term, than not.

If drivers actually obeyed posted speed limits and drove responsibly taking account of conditions, then we wouldn't need all those measures to slow them down.

radamfi said:
People on this thread have been talking a lot about fuel consumption, but this is about emissions.

See figures 3 and 4 in

https://www.eea.europa.eu/themes/transport/speed-limits-fuel-consumption-and/speed-limits

View attachment 70416

View attachment 70417

Even taking a quick look at the link it's not clear whether these are expressed per distance travelled or per unit time. If it's per unit time they need to be factored to take account of the increased distance travelled at higher speeds.

AM9 · 14 Nov 2019

bramling said:
... Ironically the biggest factors which have increased my car mileage have been ...... the arrival of the class 700s, although fortunately I’m able to avoid them 99% of the time. ...

I'm sure that the number of passengers that switched away from car commuting because they can actully get on their trains now they are class 700s, brings more than enough emissions reduction to counter your speeding down the A1M.

Bletchleyite · 14 Nov 2019

bramling said:
As regards cruising at 80+ mph, don’t forget the non-motorway section of the A1, which I find an increasingly attractive alternative to the M1

That's so winding I wouldn't want to be doing 80mph on it. I find the prevailing speed there is more like 60-65 (though it is often quiet enough for someone who wants to do even 100 to be able to do so). The motorway bit tends to be a lot faster.

Bletchleyite · 14 Nov 2019

TRAX said:
When you take into account the fuel consumption per passenger-km of a transatlantic 777 flight, the carbon footprint of that plane is tiny.
This plane-shaming business is ridiculous. And how would you travel to America if not by plane ? Electric bike ?

A modern plane is about the same when full as if each passenger had driven an average family car. This isn't great but it isn't that bad either. What it highlights is that long-haul travel in any form is an issue and should be reduced.

Bletchleyite · 14 Nov 2019

eMeS said:
Several traffic-light assisted roundabouts in central Milton Keynes seem to have had their traffic-lights switched off (& labelled with a large, narrow "X"). It's not clear whether this is an experiment, or permanent. The labelling isn't that clear the first time you come across them. Traffic flow doesn't seem to be any worse, but then I'm no longer a commuter.

There's only one traffic-light-assisted roundabout in CMK, so I don't know which other one you mean (there are only about 5 or 6 in total in the whole of MK). The lights on them are for safety at the expense of flow, as you lose time while both lights are on red[1] - they always flow better without the lights. Most likely they are just off while a part is ordered for repair.

Lights only provide a flow benefit on roundabouts with uneven flows.

[1]The A508-M1 roundabout in Northampton cleverly avoids this by only having lights on some of the arms.

TRAX · 14 Nov 2019

radamfi said:
People on this thread have been talking a lot about fuel consumption, but this is about emissions

Ah I was waiting for that answer. Emissions are related to fuel consumption. What comes out of the tailpipe is what the engine has burned.

Bletchleyite said:
A modern plane is about the same when full as if each passenger had driven an average family car. This isn't great but it isn't that bad either. What it highlights is that long-haul travel in any form is an issue and should be reduced.

oh yes and let’s all go on vacation to Skelmersdale.

randompixel · 14 Nov 2019

The demand for bigger cars is also making the issue worse.

SUVs “were the second biggest reason for global emissions growth in last 10 years, after the power sector and more than all the industrial sectors put together”, IEA director Fatih Birol told reporters in Paris on Wednesday.

Energy-intensive SUVs and pickup trucks account for about two-thirds of car sales in the US and only about a third in the EU, though they are steadily growing in demand in Europe, according to industry reports. Worldwide, about 42% of cars sold last year were SUVs, Birol said.

https://www.theguardian.com/environ...ensure-oil-demand-grows-for-decades-warns-iea

Growing demand for SUVs was the second largest contributor to the increase in global CO2 emissions from 2010 to 2018, an analysis has found.

In that period, SUVs doubled their global market share from 17% to 39% and their annual emissions rose to more than 700 megatonnes of CO2, more than the yearly total emissions of the UK and the Netherlands combined.

The recent dramatic shift towards heavier SUVs has offset both efficiency improvements in smaller cars and carbon savings from electric vehicles.

As the global fleet of SUVs has grown, emissions from the vehicles have increased more than fourfold in eight years. If SUV drivers were a nation, they would rank seventh in the world for carbon emissions.

“An SUV is bigger, it’s heavier, the aerodynamics are poor, so as a result you get more CO2,” said Florent Grelier from the campaign group Transport & Environment.

T&E figures show the average mass of new cars rose 10% between 2000 and 2016, which the group suggested could be down to a trend towards SUVs, heavier automatic and dual-clutch gearboxes and the inclusion of other equipment including cameras and sensors.

Grelier said the global shift towards bigger cars had been observed for a while, but the effect on emissions increases compared with other industries was surprising nonetheless.

“The problem is much bigger than we expected,” he said.

https://www.theguardian.com/environ...iggest-cause-of-emissions-rise-figures-reveal

edwin_m · 14 Nov 2019

TRAX said:
Ah I was waiting for that answer. Emissions are related to fuel consumption. What comes out of the tailpipe is what the engine has burned.

CO2 emissions are certainly related to fuel consumption, but locally harmful emissions are much less so. In fact some measures that reduce one will increase the other, such as the preference for petrol or diesel cars.

HSTEd · 14 Nov 2019

A lot of this stuff is politicians/campaigners coming to realise that public transport is not fit for purpose.
But rather than spend money to make public transport actually attractive, they propose to simply render all alternatives untenable.
Much cheaper, but not particularly good for normal people.

Bletchleyite · 14 Nov 2019

TRAX said:
oh yes and let’s all go on vacation to Skelmersdale.

Go to one of the many beautiful and interesting destinations in the UK, mainland Europe or western Asia (perhaps the Netherlands?), ideally by train (or if you've got a family, go by modern family car - with 4 in it's quite efficient). By all means go long-haul more infrequently, but there are people who go to Florida every year and they should probably consider reining that in a bit.

Sometimes we seem to forget that this is a rail forum!

Bletchleyite · 14 Nov 2019

HSTEd said:
A lot of this stuff is politicians/campaigners coming to realise that public transport is not fit for purpose.
But rather than spend money to make public transport actually attractive, they propose to simply render all alternatives untenable.
Much cheaper, but not particularly good for normal people.

How exactly is a top speed of 60mph on the motorway in a very small country (about the size of the South East and with traffic congestion to match) rendering anything untenable?

HSTEd · 14 Nov 2019

Bletchleyite said:
How exactly is a top speed of 60mph on the motorway in a very small country (about the size of the South East and with traffic congestion to match) rendering anything untenable?

I was referring to the inevitable comments upthread and by campaigners in the UK referring to a similar limit in the UK being desirable.

Bletchleyite · 14 Nov 2019

HSTEd said:
I was referring to the inevitable comments upthread and by campaigners in the UK referring to a similar limit in the UK being desirable.

I'm not convinced it would render anything untenable here, either. It's a 1/7 speed reduction. That won't add anywhere near 1/7 onto your journey time, as there is plenty of it where you aren't on motorways or can't reach 70 anyway.

For the record I would support the reduction of single carriageway NSL to 50 (and possibly dual to 60 with some motorway-like duals left at 70 like the North Wales Coast) but that's more for safety gains due to reduced overtaking than pollution reduction as the limit for all vehicles would be the same - the latter is just a happy side effect[1]. I think 70 works fairly well as the motorway limit, particularly now enforcement means it's not actually difficult to do 70 as it used to be (it used to involve a lot of weaving in and out of traffic going either much slower or much faster).

[1] If you want to get in your car and go and try what this feels like, a number of Councils have done it unilaterally using signage - try much of Derbyshire. Everything at 50 feels so much more relaxing to drive (and so is almost certainly much safer) but barely affects journey times.

bramling · 14 Nov 2019

Bald Rick said:
“At this point the Hertfordshire Constabulary had seen enough...”

Going off on a tangent, but this reminds me of a friend who got caught doing something ridiculous like 65 mph in a 30 limit in Edgware a few years ago. The friend in question was at the time about 60, but has one of those “butter wouldn’t melt” faces and due to a couple of health conditions looks a bit older than that.

After being pulled the exchange went “bloody hell we were expecting some young chav”. After seeing the railway uniform the conversation changed to “have you had a stressful day?” to which the response was “in all honesty no”. He was then told to drive away and enjoy the rest of his evening!

gordonthemoron · 14 Nov 2019

bramling said:
A lot more pollution could be avoided by teaching drivers how to drive efficiently (in other words maintaining a constant speed instead of slowing down and speeding up unnecessarily), and clamping down on poorly maintained vehicles.

Can't see that working in Milton Keynes due to the number of roundabouts

Bletchleyite · 14 Nov 2019

gordonthemoron said:
Can't see that working in Milton Keynes due to the number of roundabouts

You can drive in MK pretty much without using the brakes at all - that approach might be encouraged with a bit of education (and works best wit. Otherwise reducing the speed limits to 50/60 or 40/50 will be needed, and I expect that will likely return to the table soon enough - it's always been thrown out when purely suggested on safety grounds, but I think views on environmental grounds are changing and the prevailing speeds on the grid have been reducing noticeably since I moved there.

(A nice aspect of high limits is that you don't have to worry about them, as mostly you'll want to drive well below, and there are few places where you actually *can* speed in an average car)

AM9 · 14 Nov 2019

Bletchleyite said:
You can drive in MK pretty much without using the brakes at all - that approach might be encouraged with a bit of education (and works best wit. Otherwise reducing the speed limits to 50/60 or 40/50 will be needed, and I expect that will likely return to the table soon enough - it's always been thrown out when purely suggested on safety grounds, but I think views on environmental grounds are changing and the prevailing speeds on the grid have been reducing noticeably since I moved there.

(A nice aspect of high limits is that you don't have to worry about them, as mostly you'll want to drive well below, and there are few places where you actually *can* speed in an average car)

What is most encouraging is that the technology to police new lower speed limits is now proven and to the majority of drivers acceptable. Those who think that limits don't apply to them and who don't conform can then be removed from the driving gene pool.

Netherlands reduces speed limit to 100 km/h in daytime

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