New petition to getthe Government to raise motorway speed li

[Jim1556]

Vaud said:

Setting the arguments of safety vs speed aside, how about the increases in pollution?

A fairly pointless argument in my eyes as we're driving cars which are much, much less polluting than 20 - 30 years ago!

[vonhosen]

Jim1556 said:

Vaud said:

Setting the arguments of safety vs speed aside, how about the increases in pollution?

A fairly pointless argument in my eyes as we're driving cars which are much, much less polluting than 20 - 30 years ago!

Hardly pointless, what matters are the pollution reduction targets the government are setting themselves now because they will influence policy.

[Engineer792]

Vaud said:

Davidonly said:

We ought to place more emphasis on freedom of choice. I feel the state intervenes far to much where its not required to do so. The 70 NSL is out of date. Everyone knows it. An increase is supported by a significant majority. The pressure groups have also had too much sway across our society for too many years.

Government needs to grow some and do what's wanted and right.

Setting the arguments of safety vs speed aside, how about the increases in pollution?

Besides the fact that harmful pollutants tend to be higher at lower speeds, and ignoring the fact that the really big polluters are limited to 56mph, lower speeds mean that whatever pollution a vehicle does produce is concentrated over a smaller area - and the vehicle is on the road for longer, polluting for longer.

[Engineer792]

Flibble said:

It's from the drag equation: https://en.wikipedia.org/wiki/Drag_equation
This is fairly basic physics, and has been known for well over 100 years. Just because you eyeballed your (inaccurate) onboard MPG counter a few times and kid yourself 85 mph is basically the same efficiency as 70 mph doesn't mean it is. You'd hope someone who describes themselves as an aircraft engineer would have some knowledge of this!

All well and good, except that drag is only part of the equation - albeit an increasingly large part when we get to very high speeds.

Friction and other losses are mostly independent of speed, but are generally relatively small.

The big fuel users are acceleration and gravity.

Put simply, and leaving aside variations in efficiency etc, it takes a certain quantity of fuel to accelerate a given mass by a given speed at a given rate, so it takes the same amount of fuel to accelerate from 60 to 70 as from 30 to 40, assuming the same rate of acceleration.
And we as drivers probably spend a lot more time accelerating than we realise. We speed up and slow down by small amounts a lot of the time.
This is also a big part of the reason why more powerful cars tend to use more fuel - they accelerate quicker, even at part-throttle, than the driver may realise.

Similarly, we use a lot more fuel on uphills than on the level, and, although the fuel used per unit time
is higher with speed, due to the greater rate of climb, we reach the top quicker at a higher speed - which more or less balances it out.
And the greater fuel usage on uphills is unfortunately not always compensated for by the corresponding downhill sections, particularly as people tend to use engine braking and even actual braking on downhills to control their speed - so squandering all that free momentum courtesy of gravity.

[surveyor_101]

Engineer792 said:

Any idea why there are so many accidents on that stretch of the motorway?

Accidents are fairly rare on the M5 north of Bristol, and, as I understand, south of Taunton

Think most regulars do the limit or less and get quite a few heavies. Then you get powerfully built director types in big German cars or Chelsea tractors attempting land speed record. A lot of middle lane hoggers no police, means high speed differentials. Doesn't go well Lso a lot of aggressive tailgating from people Chelsea tractors and big German cars.

In the summer months it's the caravans but then the section between jct 27 down to the m5 end is bad then.

I have just done London and back m5/m4 there a303 back less dodgy driving in the 303 but I did see an unmarked bike being used for speed enforcement in the greenery!

Just before Salisbury unmarked silver bike chevrons and guy in high viz verge with looked like a speed gun.

Edited by surveyor_101 on Tuesday 21st March 20:09

[loose cannon]

PoleDriver said:

PH XKR said:

Que professional rapist/king of the road claiming their speedo is super dooper more accurate than yours

I think he was referring to the angry Hgv driver trying to push you out of the way for daring to stick at 50mph in an average speed section when clearly his speedo is more accurate and important than a mere car driver minding his own business

[PH XKR]

loose cannon said:

PoleDriver said:

PH XKR said:

Que professional rapist/king of the road claiming their speedo is super dooper more accurate than yours

I think he was referring to the angry Hgv driver trying to push you out of the way for daring to stick at 50mph in an average speed section when clearly his speedo is more accurate and important than a mere car driver minding his own business

si!

[Engineer792]

surveyor_101 said:

Engineer792 said:

Any idea why there are so many accidents on that stretch of the motorway?

Accidents are fairly rare on the M5 north of Bristol, and, as I understand, south of Taunton

Think most regulars do the limit or less and get quite a few heavies. Then you get powerfully built director types in big German cars or Chelsea tractors attempting land speed record. A lot of middle lane hoggers no police, means high speed differentials. Doesn't go well Lso a lot of aggressive tailgating from people Chelsea tractors and big German cars.

Pretty much like any other stretch of motorway then

[Vaud]

Engineer792 said:

surveyor_101 said:

Engineer792 said:

Any idea why there are so many accidents on that stretch of the motorway?

Accidents are fairly rare on the M5 north of Bristol, and, as I understand, south of Taunton

Think most regulars do the limit or less and get quite a few heavies. Then you get powerfully built director types in big German cars or Chelsea tractors attempting land speed record. A lot of middle lane hoggers no police, means high speed differentials. Doesn't go well Lso a lot of aggressive tailgating from people Chelsea tractors and big German cars.

Pretty much like any other stretch of motorway then

On a tangent, since getting a very boring non German car (XC60) with the drivers pack of lane warning, radar cruise, BLIS etc, I have found myself being a better and smoother driver on motorways. Better distance from car in front, smoother progression. I don't think I'm any slower point to point, but it feels more restful...

[surveyor_101]

Vaud said:

On a tangent, since getting a very boring non German car (XC60) with the drivers pack of lane warning, radar cruise, BLIS etc, I have found myself being a better and smoother driver on motorways. Better distance from car in front, smoother progression. I don't think I'm any slower point to point, but it feels more restful...

Just switched to a GTD and the radar guided cruise is super keen on very cautious following distances with the cruise on.

I find smooth of restful means you get there less stressed.

Got 57.7mpg on 156 miles. Then back 52.7.

In sport mode at full chat only 29mpg

[Vaud]

surveyor_101 said:

Just switched to a GTD and the radar guided cruise is super keen on very cautious following distances with the cruise on.

I find smooth of restful means you get there less stressed.

Got 57.7mpg on 156 miles. Then back 52.7.

In sport mode at full chat only 29mpg

I thought mine was cautious, but then looked and it's pretty smart, I think mine correlates if the wipers are on with an increased stopping distance, for example... I might be wrong.

I have a couple of modes - close, medium and far following but find the "far" the best - in crawling traffic it is brilliant, just ease back and listen to the radio.

[Ken Figenus]

Nicely worded official response just receiived - 'why did you even bother as its nothing to do with you' is hidden in the response somewhere

An initial assessment of the possibility of introducing trials of 80 mph limits was made in 2012-13 but we currently have no plans to do so.

You went too high - maybe if you had said '83mph to be in line with most of Europe' they might have said 'ok worth another look' rather than nothing changes and we have no plans, shut-up etc...

[0000]

I doubt it. I don't think anyone really reviews the petitions on merit, certainly with below 100k signatories, there must be at least one person whose job it is to just close these down who has no power to do anything else.

Of course there aren't any plans to increase the limit, that's the whole fking point of the petition!

[bad company]

Ken Figenus said:

Nicely worded official response just receiived - 'why did you even bother as its nothing to do with you' is hidden in the response somewhere

An initial assessment of the possibility of introducing trials of 80 mph limits was made in 2012-13 but we currently have no plans to do so.

You went too high - maybe if you had said '83mph to be in line with most of Europe' they might have said 'ok worth another look' rather than nothing changes and we have no plans, shut-up etc...

Agree and maybe if they had gone for 83mph for the reasons you give the petition might have got over the 100k signatures.

[Monkeylegend]

Going well I see, about 600 signatures this week so far, only another 79000 ish needed.

[Zirconium]

loose cannon said:

PoleDriver said:

PH XKR said:

Que professional rapist/king of the road claiming their speedo is super dooper more accurate than yours

I think he was referring to the angry Hgv driver trying to push you out of the way for daring to stick at 50mph in an average speed section when clearly his speedo is more accurate and important than a mere car driver minding his own business

Cue the whoosh parrot!

[PoleDriver]

Your whoosh is my command!



PS, it's CUE!

[swamp]

Engineer792 said:

Put simply, and leaving aside variations in efficiency etc, it takes a certain quantity of fuel to accelerate a given mass by a given speed at a given rate, so it takes the same amount of fuel to accelerate from 60 to 70 as from 30 to 40, assuming the same rate of acceleration.

This is not true, assuming fuel corresponds directly to energy at least.

Kinetic energy is proportional to the square of the velocity. In a frictionless environment, say, it will take significantly more energy to accelerate a car from 60 to 70mph than from 30 to 40.

[Engineer792]

swamp said:

Engineer792 said:

Put simply, and leaving aside variations in efficiency etc, it takes a certain quantity of fuel to accelerate a given mass by a given speed at a given rate, so it takes the same amount of fuel to accelerate from 60 to 70 as from 30 to 40, assuming the same rate of acceleration.

This is not true, assuming fuel corresponds directly to energy at least.

Kinetic energy is proportional to the square of the velocity. In a frictionless environment, say, it will take significantly more energy to accelerate a car from 60 to 70mph than from 30 to 40.

Sorry, my bad there - I was thinking in terms of MPG rather than absolute quantity, and so confused myself a bit.

So I should have said that you get the same MPG accelerating from 60 to 70mph as you do from 30 to 40

[Willy Nilly]

vonhosen said:

Jim1556 said:

Vaud said:

Setting the arguments of safety vs speed aside, how about the increases in pollution?

A fairly pointless argument in my eyes as we're driving cars which are much, much less polluting than 20 - 30 years ago!

Hardly pointless, what matters are the pollution reduction targets the government are setting themselves now because they will influence policy.

I dare say the high speed trains the government are looking to install would be considerably quieter and use less energy if they went at a nice, sedate 70 mph instead of hurtling along and a death inducing 180mph.