Thoughts on the suggested 80mph

bompington

Rick Chasey wrote:

Only in the UK would a boorish motoring programme like top gear be prime time massive ratings viewing.

With the possible exception of the other 169 countries the BBC sell it to

rick_chasey

bompington wrote:

Rick Chasey wrote:

Only in the UK would a boorish motoring programme like top gear be prime time massive ratings viewing.

With the possible exception of the other 169 countries the BBC sell it to

Is it prime - time viewing there?

On a publicy funded channel free-to-all channel?

In Holland it's buried deep in the listings.

:roll:

sfichele

Any mathematicians out there ? Whats the maximum throughput of cars driving at 80mph versus 70mph on a particular stretch of motorway.

+1

If you push cars through with a two second spacing then the number of cars flowing across a line is independent of speed!

It's 1/(timeSpacing) * number of lanes! So 0.5 * numLanes

This result needs a bit of explaining! The number of cars flowing through a stretch of motorway is theoretically independent to the speed if you enforce a time spacing. The flow then depends on the amount joining per second and the amount leaving per second.

But the time spent on the motorway by one car theoretically decreases with increasing motorway speed (theoretically).

However, there are many things that cause everything to slow down.
1) Joining a busy motor way
2) Leaving a busy motor - people wait until the last minute then cut across slowing down the inner lane.
3) Changing lanes when its busy. You slow down that lane
4) Tailgating leading to concertina effect

DavidBelcher

Rick Chasey wrote:

bompington wrote:

Rick Chasey wrote:

Only in the UK would a boorish motoring programme like top gear be prime time massive ratings viewing.

With the possible exception of the other 169 countries the BBC sell it to

Is it prime - time viewing there?

On a publicy funded channel free-to-all channel?

In Holland it's buried deep in the listings.

:roll:

Speaking of which, has no-one considered the detrimental short-term effect of increasing motorway speed limits on the BBC's finances? I'm thinking, of course, of the additional supplies of Kleenex that will need delivering to Clarkson's dressing room at the TG studios....

David

Redhog14

Is this raising of the limit to 80mph and the "weekly bin collection" BS from the govt just a smokscreen to allow them to appease "middle britain" and distract them from proper problems like, prisons, NHS, education and Policing, Afghanistan?
Frankly an extra 10mph will make no difference to me at all and I don;t actually need my bin collected each and every week.

rick_chasey

Redhog14 wrote:

Is this raising of the limit to 80mph and the "weekly bin collection" BS from the govt just a smokscreen to allow them to appease "middle britain" and distract them from proper problems like, prisons, NHS, education and Policing, Afghanistan?
.

Given that 'middle Britain' are the only people who actually decide who wins elections and who loses, it's hardly a surprise.

bompington

Rick Chasey wrote:

Redhog14 wrote:

Is this raising of the limit to 80mph and the "weekly bin collection" BS from the govt just a smokscreen to allow them to appease "middle britain" and distract them from proper problems like, prisons, NHS, education and Policing, Afghanistan?
.

Given that 'middle Britain' are the only people who actually decide who wins elections and who loses, it's hardly a surprise.

Yes, it's very strange really that politicians would want to do anything to appeal to voters isn't it? Sadly democracy is just a way of giving people what they want not what they need, it's just that it beats the alternatives we've tried so far.

rick_chasey

bompington wrote:

Rick Chasey wrote:

Redhog14 wrote:

Is this raising of the limit to 80mph and the "weekly bin collection" BS from the govt just a smokscreen to allow them to appease "middle britain" and distract them from proper problems like, prisons, NHS, education and Policing, Afghanistan?
.

Given that 'middle Britain' are the only people who actually decide who wins elections and who loses, it's hardly a surprise.

Yes, it's very strange really that politicians would want to do anything to appeal to voters isn't it? Sadly democracy is just a way of giving people what they want not what they need, it's just that it beats the alternatives we've tried so far.

My point was more than such a narrow 'real' electorate creates narrow unbalanced gov't policy.

But yes.

shm_uk

It would be more efficient if all of the cars waited for the gap and changed at the same time. In practice that NEVER happens.

That would require intelligent thought & consideration for other road users. From a motorist. It's a very tall order.

DavidBelcher

Redhog14 wrote:

Is this raising of the limit to 80mph and the "weekly bin collection" BS from the govt just a smokscreen to allow them to appease "middle britain" and distract them from proper problems like, prisons, NHS, education and Policing, Afghanistan?
Frankly an extra 10mph will make no difference to me at all and I don;t actually need my bin collected each and every week.

It'll keep the "Maily Express" contingent happy, I suppose.

David

CiB

Oh come come. Anyone would think that the govt had authorised all rep car drivers to carry small arms. It's normalising what already happens. Raising the legal limit to 80 won't have one jot of difference in the real world; where m/ways are congested the upper limit is unreachable anyway, and on those m/ways where the road is clear enough traffic settles at about 80 anyway. It just does. The police never enforce the limit below 80 anyway and this won't change that enforcement one jot. The speed limit already is 80.

It could be argued that this is the most tested law change ever.

El Gordo

CiB wrote:

Oh come come. Anyone would think that the govt had authorised all rep car drivers to carry small arms. It's normalising what already happens. Raising the legal limit to 80 won't have one jot of difference in the real world; where m/ways are congested the upper limit is unreachable anyway, and on those m/ways where the road is clear enough traffic settles at about 80 anyway. It just does. The police never enforce the limit below 80 anyway and this won't change that enforcement one jot. The speed limit already is 80.

It could be argued that this is the most tested law change ever.

+1

It's hardly a big deal to make it legal to do 80 since it won't make the blindest bit of difference.

It will please the majority of people (apart from the usual hysterical types) because it's sensible. A cynic might say they only do it to get votes but well, duh, funnily enough I will vote for a party that passes sensible laws.

beverick

C'mon folks. Read the article.

The government announced its intention to lauch a consultation on the possibility of allowing an increase in the current maximum permissable motorway speed limit to 80 mph.

1) Intending to do something and doing it are two different things.

2) They're intending to hold a consultation process, not actually change anything.

3) The review, should it take place, may conclude that the current limit is adequate.

4) Just because the maximum permissable speed limit increases it doesn't mean that it'll be adopted anywhere on the network. All we may see are the current de-restricted signs being changed out for 70 mph ones (or, more likely, 60 or 50mph ones).

5) It's the Tory party conference next week so they're looking for popularist headlines.

Personally I'd be fairly relaxed about the change, if only for the fact that 80mph is the de facto limit already. However, I would like to see substantially improved policing of the new limit where it was applied.

Bob

Pross

CiB wrote:

Oh come come. Anyone would think that the govt had authorised all rep car drivers to carry small arms. It's normalising what already happens. Raising the legal limit to 80 won't have one jot of difference in the real world; where m/ways are congested the upper limit is unreachable anyway, and on those m/ways where the road is clear enough traffic settles at about 80 anyway. It just does. The police never enforce the limit below 80 anyway and this won't change that enforcement one jot. The speed limit already is 80.

It could be argued that this is the most tested law change ever.

Phil Hammond was effectively arguing this yesterday which is fair enough. However, trying to justify it by how much it will benefit commerce is ridiculous. He had no answers on the interviewer's queries about its effect on safety and the environment. If it is just to normalise the existing situation don't put it out as some fantastic commercial benefit. Is saving 15 minutes on a 2 hour journey (something I do several times a week) really that big an issue? Commercial vehicles have different speed limits so it won't make any difference there. I'm also not convinced by the argument that people won't do 90 if the limit is 80, from my experience people have their own limits of "what can I get away with" and most will be conditioned to thinking they won't get bothered if they go 10 mph over.

Kerguelen

Well, I think it's motorways only; so no need to panic just yet.

Most people on the motorway do 80 anyway and only slow down if they see a plice car (from what I've seen anyway).

mrushton

Prob. mentioned elsewhere on this thread but stopping at 70mph requires 96m ie <300ft whereas 80ph it takes 120m ie >350ft. Now no-one on the motorway leaves 50ft never mind 300ft between cars

CiB

mrushton wrote:

Prob. mentioned elsewhere on this thread but stopping at 70mph requires 96m ie <300ft whereas 80ph it takes 120m ie >350ft. Now no-one on the motorway leaves 50ft never mind 300ft between cars

But it doesn't matter. The limit is effectively 80 now. This proposal changes nothing in the real world, other than removing the option of prosecution by some over-zealous plod.

ravey1981

mrushton wrote:

Prob. mentioned elsewhere on this thread but stopping at 70mph requires 96m ie <300ft whereas 80ph it takes 120m ie >350ft. Now no-one on the motorway leaves 50ft never mind 300ft between cars

So what? Unless the car in front is going to stop in an instant the braking distance means nothing... since the car in front will be (not) slowing down at roughly the same rate...

Mike Healey

woodnut wrote:

I think it should be reduced. They do much bigger mileages in the US with a max of 55mph.
Reducing the max speed limit to 60 and rigidly enforcing would cut our national fuel consumption massively and make little real difference to the vast majority of journey times.
Also residential streets should be 20 and those lazy bastards who park outside schools should be shot, on the spot, Judge Dredd style :idea:

55 limit abolished long since

MattC59

To be honest, I really don't care.
You don't have to drive at 80mph.
People can't drive at 80mph if the traffic isn't moving at 80mph.
The stopping distance argument is irrelevant unless you're driving at a stationary object.
Fuel consumption isn't necessarily relevant to the speed you drive at, but how you drive.

So, to conclude, an increase in speed limit will only make any difference to you if you want it to.

Here endeth the lesson.

hang on, careful, last time I said that, I was accused of being patronising !!

jawooga

A lot of people drive on motorways at about 60mph, trundling along the inside lane, and doing so quite safely. These people include the fuel conscious and older drivers.

Raising the limit to 80mph, means that the bluk flow rate on medium traffic motorways will go up to 80mph, with a large number going at 85 to 90 - the proportion who currently do 80 as a matter of course.

Suddenly life on the motorway is a lot more scary for the slower drivers and in truth, people going at 60mph would be a hazard - just as 50mph drivers on motorways now are dangerous.

I don't see there's any benefit to this. Most of our roads are too busy to warrant an increase, the government don't invest properly in repairing the roads so they're not great quality, and I don't believe the police routinely prosecute 80mph drivers anyway.

richk

90 will be the new 80...

Pross

ravey1981 wrote:

mrushton wrote:

Prob. mentioned elsewhere on this thread but stopping at 70mph requires 96m ie <300ft whereas 80ph it takes 120m ie >350ft. Now no-one on the motorway leaves 50ft never mind 300ft between cars

So what? Unless the car in front is going to stop in an instant the braking distance means nothing... since the car in front will be (not) slowing down at roughly the same rate...

Reaction time is accepted as being generally around 2 seconds for an average driver. This is taken into account in braking distances along with the rate of deceleration. When designing a road the visibility available should be sufficient to allow a comfortable decelaration rate whilst the Highway Code distances are for sudden emergency braking. The 2 seconds is what is often quoted as the distance to maintain between cars as the driver behind then has the gap to react and still decelerate at the same rate as the car in front. 2 seconds at 70mph is 31m whilst at 80mph it would be 35m. The problem is, even this sort of gap isn't maintained so vehicles have to brake harder and harder until it gets to a point where someone doesn't stop in time (or in many cases people are tired / not concentrating and their reaction speeds are lower with the same result occurring). If everyone drove the required distance from the car in front and stayed in the same lane then there would be far fewer accidents but they don't which is why increasing the speed limit will have no benefit on journey times.