New petition to getthe Government to raise motorway speed li
Discussion
Flibble said:
Than 70 mph I'd assume. Aero drag at 80 is 50% higher than at 70, and is the main source of resistance at those speeds. You spend 14% less time in the area, but use 50% more energy doing it, so energy used per mile would be about 30% higher, hence emissions in any given area will be higher (probably not 30% higher, but 20% ish seems reasonable).
These figures seemed a bit OTT so I did a little test this morning. A petrol 2-litre Ford Focus on a 26 mile run each way. Mixed roads, with about 80% on 70mph dual carriageway. A bit of 50 and a bit more of 60. The traffic level was about the same.I drove at an indicated 80 top speed on the way there. 65 in the 60 and 55 in the 50. All legal.
On the return I stuck to an indicated 60 in the 70 except where doing so would cause a bit of obstruction, such as passing another vehicle, an indicated 60 in the 60 and 50 in the 50.
On the way out I got 33.9mpg. On the return I got 40.1.
That's a remarkable saving.
When driving at 60 on the dual carriageway I was surprised how frequently I had to pass other vehicles.
General Fluff said:
Turkeys voting for Christmas. Any increase in the limit would no doubt come with an increase in enforcement. You can already drive at 85 with no risk of getting tugged.
No true been tugged for 84.Also gantry cameras on smart motorways seem to start issuing tickets from 79-82! When national is on.
sonnenschein3000 said:
Probably not going to happen but I've signed it anyway.
It needs to be talked about, its well overdue for an increase.
I also believe that if they are allowed to increase road tax with economic inflation that the speed limit should be linked to horsepower inflation
It's been previously talked about & rejected.It needs to be talked about, its well overdue for an increase.
I also believe that if they are allowed to increase road tax with economic inflation that the speed limit should be linked to horsepower inflation
The reasons it was rejected haven't gone away.
Derek Smith said:
These figures seemed a bit OTT so I did a little test this morning. A petrol 2-litre Ford Focus on a 26 mile run each way. Mixed roads, with about 80% on 70mph dual carriageway. A bit of 50 and a bit more of 60. The traffic level was about the same.
I drove at an indicated 80 top speed on the way there. 65 in the 60 and 55 in the 50. All legal.
On the return I stuck to an indicated 60 in the 70 except where doing so would cause a bit of obstruction, such as passing another vehicle, an indicated 60 in the 60 and 50 in the 50.
On the way out I got 33.9mpg. On the return I got 40.1.
That's a remarkable saving.
When driving at 60 on the dual carriageway I was surprised how frequently I had to pass other vehicles.
Drag increases remarkably quickly at high speed as it's proportional to the cube of speed. Once you get past around 50-60 mph, drag is the main source of frictional losses (rolling resistance is a larger source at low speeds).I drove at an indicated 80 top speed on the way there. 65 in the 60 and 55 in the 50. All legal.
On the return I stuck to an indicated 60 in the 70 except where doing so would cause a bit of obstruction, such as passing another vehicle, an indicated 60 in the 60 and 50 in the 50.
On the way out I got 33.9mpg. On the return I got 40.1.
That's a remarkable saving.
When driving at 60 on the dual carriageway I was surprised how frequently I had to pass other vehicles.
I noticed it quite clearly when I changed cars - my current car has about 25% less aero drag than my old car (back of envelope calcs) and gets roughly 5 mpg better mileage cruising on the motorway (40 vs 35). This despite the previous car being a more efficient engine (it was turbo vs N/A) and having better NEDC extra urban economy figures.
Even more pertinent now as the grab for the wallet just got serious - is it 100% of weekly wage for 91mph (21mph over...)? Also any day now 27 EU countries get to ask DVLA for our details and invoice the car owner (not alleged miscreant driver as we insist upon in UK...) but there is no reciprocity - we cant do the same back...
So yes, some good news would be nice now and again rather than a continual grinding down and money grab for largely trivialities...
So yes, some good news would be nice now and again rather than a continual grinding down and money grab for largely trivialities...
EU_Foreigner said:
Speed limits were raised in The Netherlands to 130 km/h, which makes travel a lot more relaxed.
It is not impossible - the Dutch have their fair share of Brake relatives as well.
Of course it's not impossible, but when the UK government have other commitments/priorities it's not that likely. It is not impossible - the Dutch have their fair share of Brake relatives as well.
surveyor_101 said:
No true been tugged for 84.
Also gantry cameras on smart motorways seem to start issuing tickets from 79-82! When national is on.
Yes, but the chances of getting tugged for 85mph are pretty low.Also gantry cameras on smart motorways seem to start issuing tickets from 79-82! When national is on.
I'm guessing some of the people who want the limit raised to 90mph do so on the basis that it'll free them to do 100mph+ without being tugged, however this simply won't happen given the inevitable increase in enforcement.
And anyway, no-one NEEDS to travel at more than 70mph as a) the UK simply isn't that big and b) the vast majority of people's journeys wouldn't benefit in a meaningful way.
ETA: To clarify, I'd love the motorways to have a higher limit however I just don't think the amendment would be worth the hassle.
The only way I ever see a higher limit being viable is if it is somehow based on the vehicle or driver.
Let's be honest, everyone tends to treat 80mph as the limit anyway, so if you raise it to 80, people will then do 90.
It'd carry more weight if there weren't an abundance of numpties out their who have only very basic motorway driving skills, and even less attention span.
So in short, if a certain category were introduced (say, a voluntary additional 'MOT' category, and/or driving cert) to allow only justified cars/person to drive at a higher speed then it'd carry more weight. Does the idea of 'Leslie from round the corner' who "doesn't know how to check bulbs and tyres" and references the "slow and fast" lanes doing higher speeds on the motorways fill me with delight? Not particularly.
Let's be honest, everyone tends to treat 80mph as the limit anyway, so if you raise it to 80, people will then do 90.
It'd carry more weight if there weren't an abundance of numpties out their who have only very basic motorway driving skills, and even less attention span.
So in short, if a certain category were introduced (say, a voluntary additional 'MOT' category, and/or driving cert) to allow only justified cars/person to drive at a higher speed then it'd carry more weight. Does the idea of 'Leslie from round the corner' who "doesn't know how to check bulbs and tyres" and references the "slow and fast" lanes doing higher speeds on the motorways fill me with delight? Not particularly.
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