Spaniards bemoan 'joke' speed limit cut Spanish drivers are less than impressed with a "temporary" reduction of the maximum speed limit on motorways from 120 to 110 km/h, which came into force today as a measure to reduce petrol imports by five per cent a year. Speaking to RTVE, a disgruntled motorist summarised: "It's a joke, they're winding us up." An …
...and now they're about the same. 110kph is 68.35mph, i.e. very close to 70, the highest national speed limit in the UK. If it's good enough for us then it's good enough for them. Besides, everyone here behaves like the normal limit is 80 anyway, I hardly expect Spaniards to do anything different.
"Besides, everyone here behaves like the normal limit is 80 anyway,"
In effect it is, as far as your car's speedometer is concerned.
Firstly guidelines state that you can't be nicked until you are doing 10% + 1mph over the speed limit. Secondly most car speedos overread by a few percent anyway, this is because the law allows them to overread by up to 10% (I think that's the right figure) but does not allow them to underread at all. So they are built to overread by a few percent to cover the manufacturer's arse. Ever noticed how your sat nave shows a lower speed than your speedo?
The end result of all this is that if you are driving at an indicated 80mph you are likely to be doing less than 78mph and are unlikely to be nicked where the speed limit is 70mph. Also, to the general horror of Daily Express readers, the police have got better things to do with their time than pull over motorists who are doing a couple of mph over the limit.
You can be nicked for doing 10% over, and people often have been, however, if you do get nicked then arguing in court that your speedo showed you on the button then the case could be dismissed (on the grounds that this is "reasonable") however the police could insist on a calibration test, which if it finds that you're over reading by 10% instead of under reading by 10% (as you're claiming) then you'll not only get a larger fine but you could also be done for perjury, if your spedo is underreading by up to 10% that's within legal limits - You'd be very unlikely to get away with more than about 5%, but it has been used to keep a licence for 101mph which otherwise would have resulted in an automatic ban (empty road, dry conditions, good light, well maintained car, clean licence), 6 points £300 fine, some would say "result".
You can use a speedo that underreads (i.e. in itself that's not illegal), however, it must not have been "constructed" to underread (Road Vehicles Regulations 1986), so if it's faulty or the wheels or tyres have been changed since construction (larger obviously) then it is a valid defence, at this point the defence will rest on what is, or is not reasonable, i.e. is the car well maintained (current MOT), were you overtaking everybody else, did you change the wheels and tyres or did you buy the vehicle second-and like that.
It's also a common misunderstanding for the legal limit for over-reading; it's not 10% it's 10% + 6.25mph. so if it's reading 80mph you could be going 67.
"the police have got better things to do with their time than pull over motorists who are doing a couple of mph over the limit."
Damn right, that's what the speed cameras are for.
Think yourselves lucky: in France it's €90 and 1 point off for going 1kph over the limit in the vicinity of a lurking cam.
"Think yourselves lucky: in France it's €90 and 1 point off for going 1kph over the limit in the vicinity of a lurking cam."
That is worse than here, we have a 5% tolerance which isn't much in a 40 zone (2Km). We just had a report that over 3/4 of fines issued (3500 every day) are for the most minor catagory of speeding.
There is little to do with "safety" in this scam, it is pure revenue raising.
http://www.heraldsun.com.au/news/victoria/speed-fines-every-day/story-e6frf7kx-1226012595295
"What difference is there between driving at 120 or 110?"
Sounds like a stupid argument to me. If he really thinks there's no difference between driving at 68mph and driving at 74mph, then he's got nothing to whine about. If, OTOH, he thinks it is a problem then he needs a different argument.
The difference is about 4miles per gallon for any of the cars in my household. 110 vs 120 is 46 vs 42 mpg.
Probably more for most "urban runabouts" for which 120 km/h and onwards is 3.5K+ rpm which means that you can kiss the fuel economy bye bye as they are designed to be fuel efficient till around 3.2-3.3. My Daihatsu definitely opens a ravenous mouth at 3.5 and starts gulping fuel dropping to as low as 32mpg on LPG/40mpg on petrol in winter.
If you drive it at less than that it is barely sipping fuel so you can easily go up to 50+mpg.
The new limit is just shy of 70mph, the (theoretical) limit on British motorways. If they clocked you doing 170kph on British roads, you'd most likely lose your licence, rather than get away with 2 points and a fine.
I'm not sure whether this makes a better argument fro raising British speed limits, or lowering the Spanish ones. To be fair, I doubt either would make any difference to the speed people actually drive at when there are no patrol cars around.
"This argument is unlikely to cut much ice with F1 driver Fernando Alonso, who was quick to criticise the new limit and warned it was so low that drivers could nod off from boredom, with fatal consequences."
Err - what?
Maybe they shouldn't be on the road if they are within a couple of kph of "dropping off from boredom"
Heaven help them if they ever get to a town, city, corner, traffic jam - anything that requires them to drop their speed by more than a few furlongs per fortnight...
Fernando Alonso was talking sense. I was a lorry driver at the time speed limiters became mandatory on HGVs. Before, the speed limit was 60Mph and my custom was to go everywhere at 100Kph...62.5 Mph in other words. At 62.5 Mph a lorry behaves differently to one that is restricted to 55Mph (the restrictors were meant to limit the lorries to 56, but 55 or 54 wasn't unusual.
The slower speed was boring enough to be dangerous. In fact I left lorry driving after a couple of close calls due to this very fact.
Drivers who spend a lot of time on the road have their reflexes and everything 'tuned' to a particular speed. Knocking 10Kmh off that speed is going to change the ground state of all those drivers to "bored out of their faces". And that's dangerous.
Try driving round and round and round in tiny circles for hours and hours of a sunday
now THATS boring.
So boring I'd be inclined to have an underling crash into a wall just behind me... to aleviate the boredom you understand.
I'm 100% with jezzas suggestion that they run on TG's test track, its an 8. prolly going to be the least boring race since turbo/ground effect days. (before the playsation generation moved in)
Facts:
Sleep Related Crashes account for about 25% of all fatal motorway accidents, rising to about half of all crashes (A roads and motorways) during the small hours.
(“Road Safety Research Report No. 52, Sleep-Related Crashes on Sections of Different Road Types in the UK (1995–2001)” ).
All speed factors together are a contributory factor for 14% of all motorway casualties (RCGB2008).
The factor of 'exceeding the speed limit' is generally 1/3 of all the speed factors.
There is clear scope for benefit by increasing motorway limits, not for reducing them.
Added to that is the displacement from/to less safe roads - a 'pull' towards motorways (the safest type of road) can only be a good thing. Reducing motorway limits 'pushes' traffic onto less safe roads, resulting with an overall increase of casualties across the road network (as well negating any supposed reduction of consumption).
Then there is respect for law. Making limits even less reasonable is a step in the wrong direction.
Many years ago, I used to whizz around 80-90mph from London to Bath, and fill up at the other end. I had a 1L car, and it used to cost me just over a tenner. Then one Easter, it was just sheer weight of traffic - I couldn't get above 50 ... all the way.
When I filled up, it was just over £7 ... a damn near 30% increase in fuel efficiency, just by going 50 instead of 90.
Never forgotten that lesson ... which is why I get c. 44mpg from my 2.2L diesel, while in-laws are lucky to get 25 from their 2.0L diesel ....
I drive too fast, cos i like it, my car is thirsty as a result, and I accept this, (square law of wind resistance and all ) .
But do not tell me you get there any quicker by doing so! it is simply not the case.
my sat nav smugly estimates my TOA on any journey, and it is always pretty much smack on.
I am often minded to drive like a headcase to beat it, the best i can recall beating it by was about 3 minutes....... in a 5 hour journey.
Here's a question: what happens when *everyone* drives slower?
On one hand, everyone could improve their MPG - and reduce wear/tear on their vehicle - the engine isn't worked as hard and tyre wear should be reduced. Lower speeds may also reduce the frequency/severity of accidents, too, as people will have more time to react.
On the other hand: cars will be spending more time on the road - they'll physically occupy a given stretch of road for longer.. Roads have a fixed capacity, so this is likely to lead to increased congestion and traffic jams, especially during peak traveling hours. Which in turn could increase pollution and the risk of vehicle failure (e.g. cars sitting stationary and overheating).
There's also a number of other potential side effects - there's a small but potentially critical increase in both personal and commercial costs; the individual spends longer driving, which increases fatigue and the risk of road-rage and aside from the delay to goods delivery (esp. since truck drivers have to abide by the clock), people travelling for work will have to schedule more "dead time" inbetween activities, reducing their effectiveness - and the company may end up paying for this directly if it's an organisation which treats business travel as working hours/TOIL.
All told, has anyone ever done a study of the side-effects of changing speed limits? I know Top Gear recently did a smug "toldyouso" piece on the removal of speed cameras, but they're not exactly the least biased or most scientific observer available!
On a vague tangent: one place I'd love to see the stats for would be the A14 around Cambridge. They originally had yellow-box photographic cameras scattered along the road's length; these were then disabled for a few months while they installed a set of average speed cameras.
The road was PITA when the photo-cameras were in place, as many drivers stuck to an imaginary "60mph" speed limit until they were clear of the stretch, causing vast queues to form behind them. Things seemed to drastically improve when the cameras were disabled, and then went instantly downhill when the new cameras were activated - with the added bonus that driver stress levels shot through the roof due to the need to keep glancing down at the speedo...
Often the overall traffic flow goes up. Non-linear effects produce surprising results, y'know.
Also, if you really find it stressful to both have to look around you and occasionally glance down at the speedo, you need to go and get yourself some refresher lessons, since it's a pretty basic part of the skills you need for driving. Turning the wheel and pushing the pedals with your feet is the easy bit, anyone can do that; the skill in driving all comes from situational awareness and using it to guide your decision making.
The capacity of a road varies according to the average speed of the traffic on the road. That's why when the number of drivers on the road increases, the average speed comes down. I believe that it has something to do with the distance between cars reducing as the average speed comes down so you can fit more cars per mile of road.
As far as the A14 is concerned, I've found that driving on the Cambridge->Godmanchester stretch is slightly less frightening since they switched on the average speed cameras. That said, the road is an abomination and short of digging it up it's hard to imagine how the new cameras that are being installed will improve it.
As you should increase the gap between cars with speed (at least in proportion to speed, arguably more), then the increase in car density balances out the slower speeds. Of course once the traffic density hits a certain level then the flow becomes unstable, but generally a motorway with cars travelling at 50mph will allow for greater carrying capacity than one at 70mph. That is the ostensible reason for variable speed limits on some parts of the M25.
It's my experience that traffic is travelling slower on motorways, not just because of congestion, but due to a desire to save money on fuel. Indeed it's more than that - with modern asbestos-free brakes, the wear on disks means that heavy braking can lead to heavy maintenance costs. I think I've seen considerably fewer drivers on motorways relying heavily on their brakes.
Overal UK fuel consumption is down a lot over the past decade or so, some of which is down to changed driving habits.
Your assessment is wrong. You neglect breaking distance. It has a non-linear relationship with speed. The faster a vehicle travels the greater the space that is needed around it. Throughput is increased by reducing speed - the optimum speed for throughput bearing the breaking distance issue in mind is about 40MPH. This is why the variable limits on the M25 work to clear congestion, reducing the speed limit as the road gets busier increases traffic throughput.
but in my aged 2.0 straight-6 petrol I normally get just over 400 miles (so say 650km) to an 80 litre tank on dual carriageways/motorways (70-80ish mph). That's 22.3 miles per gallon. Which is piss-poor, I'll admit, but hey- it just means that I can buy a big V8 without worrying about mpg figures...
On the same road going at 40mph (on a space saver) I used almost exactly the same- 1/4 a tank in ~100 miles. I'll admit the needle was probably inside the marker rather than outside it so it wasn't utterly useless, but to be honest I'd rather spend an extra couple of quid and get home in half the time.
However, when I went out for a drive a few months ago (after a special on eco-mentalist driving, I guess) I had to dodge and weave between waves of people driving at 50 or 60mph. Speed up, slow down, speed up, slow down- I needed to fill up again after only about 300 miles. A massive, marked difference.
So I think all these "she only got 40mpg, but I got 65!" style comments don't just reflect the speed you're travelling at- they also reflect your driving style. If she's racing back to see you, Bonnie Tyler blaring, avoiding slower cars on the multilane roads and overtaking on the single-track roads but your just lazily cruise along singing along to Radio 4 you've got two totally different driving styles.
Yes, yours is better for fuel economy. But adopt your more laid-back driving style at 80mph and you'll soon see that your speed is making a lot less difference than you thought.
"lazily cruise along singing along to Radio 4"
What do you listen to on Radio 4 that you can sing along to?
The only thing I can think of is Desert Island Disks, and you don't even get the whole tracks on that. Or maybe it is the music rounds of "I'm sorry, I havn't a clue" such as "Pick up Song", which I admit it is difficult not to sing along with, but which only lasts for a minute or two!
I find (especially listening to the Today program interviewing politicians) that I get angry, and end up shouting, impotantly, at the radio!
At 110/120km per hour on a level road, the drag due to air resistance is the dominant force to be overcome. The drag will go up roughly to the square of speed, and this means the power required goes up as to the cube. Of course you are travelling for a proportionately shorter period of time, so the reduction in power required will be about 16%. Of course there is also rolling resistance (which is more like a linear relationship), so the actual power requirement reduction is less than this.
Roughly spekaing, you could reasonablyt expect an approximately 10% reduction in fuel usage for a given distance on flat ground by travelling at 110km/hr instead of 120km/hr. Of course there will be a considerable mileage which is not on motorways, but an overal national reduction of 5% sounds achievable.
Those with a long memory will recall the US introducing a blanket 55mph (88 km/hr) national speed limit in reaciting to the 1974 oil crisis. Given the appalling road traffic accident rate in the US these days, then they might want to consider re-introducing it (in the '70s US road traffic accident rates were comparable, or better then the UK's - now they are much worse, about 3 times higher per head of population twice as high per passenger mile).
The UK government introduced 60mph speed limits on dual carriageways and 50mph on non dual carriageways for the same reason (motorways remained at 70). However, these restrictions were removed much quicker than the US measures.
to miss the point ...
Internal combustion engines (whether by design, or physics, I don't know) have their maximum efficiency around 3000-4000 rpm. If you look at your speedo, in top gear, you'll find that 3,500 rpm is roughly 55 mph ... which is where you get maximum fuel efficiency.
Drag does play a part, but it's relatively trivial at those speeds.
Sorry, but technically speaking, you are what's known as somebody who hasn't got a clue. I'll make a guess now that you barely made GCSE science, but I'd happily swap physics qualifications.
As to the optimum thermodynamic efficiency of an engine. Well that depends on the fuel it uses, the efficiency of combustion and all sorts of other things. It's certainly not the case that car diesel engines are most efficient at anytthing like 4,000 RPM (mine Focus diesel will be a bit of 2,000 RPM). In any event, it's completely irrelevant. Cars are supplied witrh gearing systems for very good reasons, and one of those is to allow an engine to run at a reasonably thermodynamically efficient RPM and power output at a given road speed. However, optimising the thermodynamic efficiency is only part of the equation - the other issue is reducing the energy required to overcome resistance. That can be done through things such as reducing rolling resistance (e.g. by higher pressur tyres, reducing car weight) and drag. The latter can be achieved by improving aerodynamics, but also by reducing speeds, and at 70MPH air resistance is the dominant factor.
Typically modern cars reach their optimal duel efficiency on flat roads at about 55mph.
Sorry but your calculations are rubbish, first we must assume that most people in this country drive diesels and not petrols (I believe the number of new cars sold in the uk is now about 80% diesel). Diesel engines have a much lower rev range than petrol and most redline at about 4-4.5k rpm and would "cruise" somewhere between 2k and 2.5k. My diesel Saab happily sites at 80mph at just over 2k rpm. Petrols on the other hand tend to rev much higher, usually about 6.5-7k and depending on gearing they would be doing 80mph in the 3k-3.5k range. My petrol Volvo does 80mph at 2.7k, so how you get 55mph at 3.5k i don't know as I believe most cars would be in 3rd gear to get that response.
The most efficient way to drive a car on the motorway is to go as slowly as you can in top gear while still maintaining the torque of the engine i.e. not at the point of stalling but at a point where you can accelerate away in top gear.
So I agree with you that it is usually somewhere in the 50-60mph range.
What cross-grained moron downvoted this.
It's a FACT - my wife's TOURAN is the same - for that matter every car I've ever owned has been better than 20 mph /1000 revs (since 1969). My motorhome at 3.5 tonnes does ~30 mph/1000 revs.
For goodness sake disagree with an OPINION but this info. is available on VW's website
If your car is doing 55 mph @ 3000 rpm you NEED TO CHANGE GEARS!
I remember that retarded speed limit. I used to live in the US back then, and wondered why the hell did the US have such a slow-ass speed limit. Given US distances, it meant that most trips were a multi-day affair.
110 km/h is the standard speed limit in Mexico, but cops will only go after you if you go over 120 km/h.
Is of course completely different depending on what vehicle you drive. The type of fuel, gearbox, and size are all important factors. Those figures might work for you but intelligence is required on the part of the driver to work out what is best for them, the vehicle and their goals.
I fear that you are commenting on a subject about which you know very little and most of that is wrong.
"to miss the point ..."
No, he was discussing other possible effects of reducing the speed limit. Much of it is marginal or irrelevant, but it does speak to the point
"Internal combustion engines (whether by design... yada, yada"
I think you are confusing maximum efficiency with peak torque. The former would be the point where the engine does the work required for the least cost whereas the latter is where the engine provides the most motive force. There is no reason the two should coincide in real life as the former is overwhelmingly dependant on environment and situation.
Those numbers you quote may be correct for your car. They do not apply to every engine at all and gearing can be different even with models of car.
"Drag does play a part, but it's relatively trivial at those speeds"
Oh yes is it does! At 100km/h drag is the overwhelming limit. All others are vanishingly small by comparison. Drag is proportional to the square of the speed (from memory - please correct me if I'm wrong) so doubling the speed quadruples the work required to push the car along.
Drag goes up as a higher power of speed than the square. AAIR the cube, at sensible road speeds, although any power law is an approximation to a complicated function that depends on several variables including vehicle shape and ambient temperature. (The drag curve goes almost vertical close to the sound barrier :-)
There's a second significant fuel saving. When traffic is dense, a lower maximum limit reduces the tendency of traffic to bunch up and then to suddenly slow to a crawl (requiring waste of energy in braking). That's why the variable speed limits on the M25 are a good thing on the green front.
I'm not sure what you're driving, but I can't remember the last time I saw a vehicle with gearing that low, normally you see 20mph per 1000rpm in top, if not more.
My 2.5 litre 6 cylinder diesel auto locks into torque converter bypass when cruising which means 80mph is just over 2000rpm... So I would be better off sitting at 140mph...
Mines the one with the cancelled licence in the pocket!
The USA accident rates have nothing to do with raising the speed limit back to 70 mph. In actual fact, the accident rates in 1997 following the lifting of the 55 mph restriction were the lowest since the late 70s. (It's the same seemingly counter-intuitive effect of speed cameras in the UK).
Having lived in the UK for 30 years, and having driven all over Europe, my own opinion of the US accident rates is that skill level of US drivers is generally appalling by northern European standards. USA drivers have always had terrible lack of situational awareness, being distracted by eating, putting on makeup, shaving, whatever. On one one recent trip across the desert on I-10, I saw some idiot in a pickup lifting dumbbells ffs (namesake, no doubt).
The advent of higher levels of in-car technology has only exacerbated the situation. Lowering the speed limits won't pull people's heads out of texting, Facebook, or their collective asses (arses if you prefer).
Yup, just proved that over this weekend. Had to do a 600 mile round trip this last weekend and actively worked at keeping the speed in my Land Rover at 55mph. The result was 36mpg as opposed to around 30mpg. What's more, it was pretty relaxing, not tensing up to overtake, compete with, stare down and generally not behaving as aggressively as speed often make us behave.
Interestingly and on another topic, we stayed with friends who have a Lexus hybrid, and he was saying he can't get more than 31mpg....
120km/h = 74 mph, give or take.
110km/h = 68 mph, ditto.
Alonso? A man who spends his life in fast things will be bored at 110km/h. The rest of us? Not so much...
In terms of fuel savings, a quick Google throws up some figures. At 60mph the power needed to overcome air drag and rolling friction is in the region of 25hp. At 70mph the same vehicle now needs about 40hp. There's obviously going to be a fuel saving. It's also non-linear, a vehicle travelling at 40mph has a figure about half that of a vehicle travelling at 60mph.
You missed two major concepts when you skimmed whatever page Google took you to.
The power required depends on the aerodynamic resistance of the vehicle. It's not a constant. Alfa Romeo got better than 100mph on 25hp from a production car in the 50s. It was small and slippery. The bigger the frontal area and the less aerodynamic the vehicle the more power is required to push the air out of the way.
Those numbers you quote are increases not absolutes and apply only to that car.
Better to understand the physics behind it than blindly quote numbers. The drag is proportional to the frontal area and the square of the speed. If you double the speed you quadruple the power required.
Now, the amount of fuel burnt to make that power is another matter altogether...
> Better to understand the physics behind it than blindly quote numbers.
I'm afraid you failed to understand part of it.
> The drag is proportional to the frontal area and the square of the speed.
True, for a given shape.
> If you double the speed you quadruple the power required."
No. The force (aerodynamic drag) is proportional to the square of the speed. The power required is (force x speed), so power is proportional to the cube of the speed.
Hence, double speed requires 8 x power.
NB this all ignores friction effects.
"The UK 70mph motorway limit was originally imposed as a means to save fuel during some fuel crisis or another. So we've all been there."
No, a 70mph upper limit on all roads was first introduced in 1965 in response to the number of deaths on the roads (and in particular probably the new fangle motorway things) in high speed crashes. The "fuel crisis" change was in the 1970's where the limit was dropped to 50 on single carriageway and 60 on dual carriageway roads with motorways remaining at 70. After a couple of years or so the upper limits where increased on single and dual carriageways to the current 60 and 70 with motorways again remaining at 70.
I used to drive around 75-85. Now I tend to do 55-70 (unless I'm really really late for something!), and I find it more relaxing, the car's more stable, your not scanning as far ahead for any pillock pulling out in front of you without indicating, in fact you spend the majority of the journey in the centre or even the inside lane* with others overtaking you! Much less stressful.
* Yes, there IS an inside lane, and no, cars ARE allowed to use it, not just lorries. In a traffic jam it's often the lane that moves the fastest :-)
Rumble strips were first introduced in the '50s on the Garden State Parkway. The technology was little-used, mostly on an experimental basis, until the late '80s, in response to an April 11 1986 USDOT-issued directive endorsing their use to reduce accident rates. That in no way "coincides" with the introduction of the 55mph limit in 1974.
Source: the "History" backround section of the report "An Evaluation of Shoulder Rumble Strips in Montana (MDoT, Research Section, 2003)"
http://www.mdt.mt.gov/research/docs/research_proj/rumble_final_report.pdf
Rumble strips were not introduced in the US with 55mph limits. In many cases, they weren't introduced until the 55mph limit was upped to 65mph. (Most US highways have 65mph or higher (e.g, FL ~= 75mph) limits.)
Their primary concern is people going off the road for *any reason* -- not just for falling asleep. And falling asleep on the roads isn't just caused by boredom. The geographic size of our country has led to some people (e.g, truckers) driving for over ten hours at a stretch, which gets dangerous at pretty much any speed.
Finally, you are in no position to identify your prime attentiveness range. One of the side effects of tiredness is a decreased ability to properly judge one's own abilities and attentiveness.
I drove from Motherwell to Carlisle (85 miles) last week for a job interview at a steady 70, and was amazed at how I only used about 9litres of fuel compared to the usual 12-13 when I have a mad dash.
But, in response to what you said about the inside lane. I learned this lessons on the M6 when I used to drive from Bristol to Glasgow every month. Especially between Wolverhampton and Preston. The inside lane usually does move faster than the outside, because the outside is full of Audi's. BMW's and Merc's all pushing their way north.
having moved to a role involving a fair bit of driving, I now get on the motorway, get to 70mph (as measured by sat-nav, so speed reads 73) hit cruise control, and trundle down the inside lane, pausing only to move out in advance of a lorry, and move back in when clear. Very relaxing, get to destination feeling alert and fresh.
Much easier than *trying* to hit 90mph all the time, and slowing/speeding up.
It might be less stressful, but that does not imply safer. As you mentioned, you are spending less time scanning ahead for problems and may become inattentive.
A bit of stress can keep you concentrated. That is one of the reasons for having bends in motorways – it gives you something to do!
No idea if anybody has bothered to actually study this though.
Stress also reduces your capacity to cope with sudden unexpected events. If you work on the premise that your brain can only cope with a certain amount of inputs at once, I'd rather have mine running at 30% than 60% whilst in charge of a ton and a half of metal travelling at high speed. Not to mention the reduced reaction time of 80mph over 60...
Nice theory, but bollocks in practice. Your brain does not have a "system idle" task to take up the slack. That spare 70% will get spent daydreaming, planning your next meeting or listening to the radio.
You should be 100% concentrated on the task in hand when driving 1.5 tons of metal at high speed down the motorway, and that is stressful.
Stress, is relative though, so you should not allow it to become too stressful, but a little stress keeps the mind focused.
Yes, there is an inside lane, unfortunately it's usually the one with the huge wheel ruts in it from the HGVs! I used to drive a lot of miles too and from a client, and regularly used to come back via the M3 in the early hours. I do like to play by the rules and not sit in the middle lane, but going in the left lane generally meant picking which wheels I wanted to sit in the rut, with the other side generally about to roll down into the other rut and fighting it all the time!
They could at least give lorries the same narrow car wheel spacing, at least then we could use the damn ruts as rails!
Re jams, jump in the with lorries every time! Apart from anything else, when you have some tosser come down the outside and want to jump in at the last moment, the lorries just ignore them and leave them stranded on the outside! (Or in one case I saw, let them plough straight into the cones! I almost had to pull over I was laughing so much!).
I wouldn't worry about that. Recently a council delegation came to Madrid to look at refuse collection here and I doubt very much that anything they saw will be implemented in the UK. Overnight collections everynight, removing stuff left at the side of bins and well publicised periodic collection of large items such as furniture.
I rather suspect that once they'd seen how efficient and successful refuse collection is in Madrid they'd wished they'd gone somewhere else.
Same down here in Andalucia - the bin lorries come round every night at about midnight and take everything. There are plenty of street-side recycling bins too.
Meanwhile in the UK, my Nan's collection has dropped to weekly (recyclables) or fortnightly (general) and it appears they actually pay somebody to sift through your 'standard' rubbish and charge you if you're not recycling things (no I'm not a Daily Mail immigrant-botherer, that's actually on the council's published material). My sister has to pay if she wants a recyclables collection. In view of fairness, other places are pretty reasonable.
The main thing that affects fuel consumption is how much you rag your engine.
As a rule of thumb, once your revs go above 3,000 your fuel consumption sky rockets. The spanish government probably did some study as to what would be the most effective reduction in speed to save the most fuel as an average accross all car types and came up with 110kph.
They probably figured that if they reduce everyone's speed on the motorway, then the nations spend on imported fuel will drop by a hell of a lot saving the economy a shit load of money.
But, it sounds like they didn't bother to explain any of that to the general public who just see it as yet another stupid government thing.
Do yourself a favour, reduce your speed on the motorway and save a shitload in petrol costs.
To paraphrase a Caledonian starship engineer, it's the laws of physics.
Power required to overcome wind and friction is proportional to speed cubed. More likely the Spaniards did a simple what reduction would people not really notice calculation, came up with 10%-ish, rounded the numbers off and realised that would be a nearly 23% reduction in power requirements. No ragging reduction needed, although that would be a side effect :)
Small little city car doing 70 will be hurting it's fuel economy compared to average, large engined cruiser will be hurting it's economy by being sub-efficient.
Banning excessive use of the breaks would probably improve fuel economy far more than a simple reduction in speed limit.
As others have said, 110 is fine, and probably saves a fair bit of fuel. It's not as if they've halved the speed limit or anything like that.
I'd quite like to see something akin to the system in France, where there are wet and dry speed limits on the motorways - 110 and 130 respectively.
The article just says they want to reduce their imports, not why. If you read the second Spanish article linked to, it's because of the rising prices of oil internationally and the weak state of their economy that they want to reduce imports; it's a balance-of-payments improvement measure, and it also helps with their CO2 targets.
Also, they're heavily dependent on Libyan-sourced oil (second biggest source of their supply), at least currently. That could be a bit iffy in the immediate future.
Alternatively, if there really is an energy crisis instead of some short-term need to bring in more cash because the country's broke, they could raise fuel or road tax or even link road tax to fuel economy, which they still haven't got round to doing yet.
The equivalent of road tax here is most certainly related to fuel economy*
The difference is that it is applied by the local council where you live rather than nationally. Having just changed to a snail-like Corsa diesel Eco car, our car tax is now a paultry 12€ every 6 months :)
* I am talking about in the mountains just north of Madrid. YMMV :)
"When my partner lived in Newcastle, she'd travel to see me at about 80mph. She'd get about 40mpg. I'd do the trip in the same vehicle, at 60mph, using other traffic as wind-breaks, and get >65mpg. "
So from this I conclude that she was 4/3rds as keen to see you as you were to see her. Bit of an indictment, eh?
( Actually I thought you were going to go on to set a problem about men filling a bath with five buckets, etc...)
It's more a case of her not liking motorways and wanting to be off them ASAP, whereas I enjoy the drive and don't mind going more slowly. That and the fact that she has reactions like a cat, and I have reactions like a 4 day old corpse.
And (I forget who it was said it above) it is possible to benefit from others wind-break effect without tailgating.
Beer, 'cos there's 40 of them in the bucket that fills the bath...
A day in court for anything over 120mph? Bargain! It's 100mph here...
Also - if they're reducing speed to pretty much match us, then they must have access to our country's combined mpg average. Are we really 5% more economical than the spanish - something I find extremely improbable?
Why would the Spanish government care about reducing fuel imports? Feel free to correct me if I've missed anything here...
1) Spain has recently been bailed out by the EU, and is a bit short of cash.
2) Spain (as in the government) doesn't pay for the fuel, the customer does.
3) Spain (the government) will of course tax the fuel, and probably add something like VAT on as well.
4) Customers (the residents of Spain who are complaining about the new limit) buy the fuel, pay the fuel tax and pay the VAT.
5) The more fuel the customers use, the more tax will go to the government and vice versa.
So surely if everyone slowed down, the government would very quickly find itself short of cash again? A bit like the UK government would if we all stopped doing the things they "say" they want us to stop doing (and tax heavily), drinking, smoking, starting our vehicles etc.
-> 2) Spain (as in the government) doesn't pay for the fuel, the customer does.
So Spain (as in the government) and the customer (e.g. the Spanish citizen) are two opposite entities? The Spanish citizen sends money abroad to buy fuel (Spain gets poorer by X) but the Spanish government gets a bit of that money (so Spain gets richer by 0.X).
Oh dear....
That would of course assume that the Spanish government are actually in it for the good of the country as a whole and not their own personal gain... More money in govt kitty = more juicy contracts for friends and a healthy public service pension pot...
Maybe I've just been exposed to the UK political system too long!
"No, a 70mph upper limit on all roads was first introduced in 1965 in response to the number of deaths on the roads (and in particular probably the new fangle motorway things) in high speed crashes."
No. The limits were introduced after the press latched onto some high speed testing on the M1 back around 1965. I believe Jaguar with the E Type and Aston Martin were the main culprits, but the press made a fuss and a 'temporary' 70 limit was brought in, in response to public outcry - won't someone think of the children, I expect.
1) Find a crisis (gas prices are going up!)
2) change something that ultimately will have very little effect (speed limits)
3) Step up fines in the name of "cracking down on dangerous drivers"
4) Profit!
They are trying to import less fuel - because fuel is expensive - by lowering speed limits, which will result in more speeding fines. I would like to see a ratio of "money saved buying fuel" and "money lost to fines", before I make a judgment on whether this is a good idea or not...
There was a kite-flying exercise the other week from the Govt, suggesting that the limit could be raised to 80 on UK m/ways.
http://www.telegraph.co.uk/motoring/news/8350157/Motorway-speed-limit-could-be-raised-to-80mph.html
It wouldn't make much difference. The limit is de facto 80 already (well explained earlier in the 2nd post, re 70 + 10% + 2mph (not 1) = 79, APCO Guidelines for prosecution) as all that would happen is that the new limit would be more rigidly enforced - I'd expect the 10% allowance to be reduced for m/way limits being exceeded.
In reality providing the conditions are ok and you're not driving like a knob-end anything less than 85 on a motorway is unlikely to result in prosecution now. With a new limit the prosecution would kick in at err 85, so no change there.
[Disclaimer - YMMV obviously]
Well, partially normal. Here in Finland, there are summer speeds and winter speeds (as well as other requirements like legally-enforced summer and winter tyres, etc).
Summer speeds:
Motorway, 120km
Major road, 100 or 80km
Minor road, 80 or 60km
Winter speeds:
Motorway, 100km
Major road, 80 or 60km
Minor road, 60km
Exceptions do also apply, but that's the gist of it. Of course, these changes exist for a meteorological reason and not just arbitrarily, but still, a mere 10km reduction is hardly anything to whine about. Not that it'll stop all the crap drivers who would normally do 140 on a 120 road from doing 120 on a 110 - at a minimum.
Fuel efficiency is better served by avoiding braking and accellerating hard.
Especially braking. If you can anticipate the road conditions and smooth out your journey, you'll use a lot less speed.
Cutting your speed - to some extent - will reduce your fuel consumption, but mainly it's about maintaining a steady speed.
As for being safer - your risk of an accident on a motorway is (I read somewhere) more to do with the time you spend on it than the speed you travel. Judging by the collosal number of secondary accidents I saw queuing on the M40 the other day going at 10 mph for an hour seems to cause a huge number of accidents.
Modern cars have better aeordynamics, better brakes, more efficient engines. People are already slowing down to conserve fuel. Safety and fuel efficiency would be better served spending money on repairing the road surfaces than amending speed limits.
Now all we need to do is make it an offence punishable by public beating with a rolled up Daily Mail to sit in the middle lane at 60mph when the inside lane is clear, and traffic could move freely, quickly, and efficiently up and down the motorway.
Only problem if the ConDems do put this one through would be we'd be stuck with it - it's illegal to pull a u-turn on the motorway (boom boom)
Speed limits in Spain are a total joke. I live here and nobody, not even the police, seems to take any notice of them, especially on the autopistas. So the government just spend a load of money changing road signs for nothing. Or possibly to keep a few people off the dole queue.
(...)Speed limits in Spain are a total joke. I live here and nobody, not even the police, seems to take any notice of them(...)
I live here as well and I must correct you
1. It's not "even the police", it is "specially the police"....
(Speed cameras do exist so it is a joke once you have memorized where they are).
BTW: you can play a nice, (albeit a bit dangerous), game when in Spain:
- If you happen to know where the speed cameras are and you also happen to have a tailgating idi...mmm fellow behind you can always speed enough so he stays tailgaiting you and speeding (the faster the better), combine it with something that ennerves him/her like decreasing speed and not letting him/her get ahead of you.
When the speed camera gets real close, change the lane and step on the brakes, (so YOU don't get a ticket), allowing him/her to pass. 99% he/she will get a hefty ticket.
Please take due note that I am not endorsing this kind of behaviour, of course not, who would want tailgaters to get 600€ fines? not me....no no
"They point to studies suggesting that a 10km/h reduction in speed saves closer to 5% on fuel rather than 15%. The government's own figures suggest it could forfeit large sums in tax revenue due to the fuel savings. And the bill for changing the road signs for just four months runs to 250,000 euros."
Mind this is the same BBC that has 130kph translating as 75 mph or 81 mph on two adjacent lines
"If you look at your speedo, in top gear, you'll find that 3,500 rpm is roughly 55 mph"
What kind of car have you got? Mine would be doing over 70.
I'd have thought that driving in top gear at the lowest speed the engine will comfortably run at would be most fuel-efficient given the way air resistance rapidly ramps up with speed. Isn't that how Clarkson got that Audi from London to Edinburgh and back on one tank a few years back?
More plausible would be to say 50% of your total achievable rpm's = 65-75 mph in top gear (for most European tin boxes anyway). Different engines have different characteristics, but the rule works. It's not hard and fast, but optimum efficiency tends to be where the engine makes most torque. This is how Clarkson did it - he balanced outright speed with the optimal torque rpm of the engine. Oh, and he had a massive tank.
Which works for cars, but doesn't work for bikes - most sports bikes are comfortable doing 80-110mph+ at 50% of total rpm.
Bikes are great in some regard...you can do a 1000 mile trip through Europe and UK recently in 14 hours of ride time (16 hours actual), and average 59mpg. It's impossible for 99% of cars to do this. Some bike journalists have done the same trip in 12 hours, though they won't be admitting that in public. Their average was nearer 40mpg, so the "cube rule" definitely applies. Speed can be economical, once you get rid of all that extra metal & weight, and you know the optimum efficiency rpm of the engine.
AC, for obvious reasons.
Of course going faster uses more fuel. Those who think 55 or whatever is 'the most economical speed' are deluding themselves.
If you're doing 45 and want to do 55, you open the throttle and when you're doing a steady 55 you'll notice the accelerator pedal is further down than it was at 45. You're squirting in more fuel per bang. Same number of bangs per mile, ergo more fuel per mile.
(...)Of course going faster uses more fuel. (...)
Sure, 1st gear and head to your destination...the consumption will be horrible my fellow Register reader.
Have you ever ridden a bicycle? With gears? Please do and you will see the point once you've realized that the slowest isn't always the less costly.
Depending on the car it can quite different. On my Corolla Verso D4D 136CV I've had to say goodbye to the 6th gear...it won't do with 110kph, so I am actually consuming more diesel at 110 than I was doing at 120...and the car's systems tell me I am right.
Given that 55 miles per hour is the speed limit adopted by the U.S. as an emergency measure in response to the oil crisis, I would have expected Spain to go to the equivalent - 90 km/h - not just from 120 km/h down to 110 km/h.
Since 60 miles per hour was the sensible speed limit on normal highways (instead of very special freeways designed for extra-fast traffic), 95 km/h is another reasonable possibility. 55 miles per hour was too slow at least for truck drivers, who found it much harder to meet their schedules and so on.
As trucks have a completely different set of speed limits, you'd have to go some to affect them- they have a 40MPH limit on single carriageways, 50 MPH on dual carriageways and 60MPH on the motorway. Coaches are limited to 50,60 and 62 respectively (65 on the motorway, ironically for older vehicles...)
(in a purely Lewis Caroll naming convention way)
To the first AC: I (like to) believe my driving style is both safe and skilled - I keep a two-second gap between my car and the car in front - which means I often have to brake to avoid ramming into people who believe that a 2-second gap makes a perfect space for them to change lanes into - and I monitor both general traffic flow and the cars several spots ahead of my own; generally in the event of a slowdown, I'll be braking/preparing to brake several seconds ahead of the car in front of me.
What I was referring to was the joy of trundling through an average speed camera zone - for instance, the 12-mile stretch of roadworks which used to sit on the M1 at Nottingham. Not only do you have to monitor your own speed, but the traffic bunches up, so you have to deal with people behind you crawling up your boot in a mission to stay at 51mph and people in front braking down to 40mph whenever a SPEX camera appears.
In other words: not fun.
@AC2: that's a fair point about coaches and trucks; I was actually thinking of more "individual" vehicles - white vans/medium sized trucks (e.g. UPS delivery), sales people, long distance commuters, etc.
For instance, I know someone who does a lot of travelling for his work, both inside the UK and abroad (USA, Europe). On a given week, it's not uncommon for him to clock up 1000+ miles bouncing between airports, customers and the head office. With an average speed of 65mph (70mph on the motorways, minus rest breaks and town driving), that works out at around 15 hours of driving per week (3 hours per day); if this dropped to 55mph (e.g. 60mph on the motorways), then he'd be stuck on the road for another 3 hours or so per week, or another 40 minutes per day.
So: there's a personal cost: he'd be more fatigued at the end of each day - and he may have to give up more of his personal time to make up some of the difference. There's an efficiency cost: he can't attend as many meetings in a given day and his work-performance may well be impacted by the increased fatigue. There's a financial cost to the company: between his wages and employee overheads, those 3 hours could cost them around £150 with no benefits to either the company or the employee.
But hey: he'll save fuel, right? Let's say his Volvo TD goes from 40mpg to 45mpg when it's trundling around at 60mph. How much will he save per week? About 2.5 gallons, which is around £17 (based on £1.36 per gallon of diesel). Even if we go up to 50mpg, he's still only saving around £31, at a cost to his health and social life, a higher risk of a fatigue-related accidents and a significant financial cost for his company. Does that really balance out?
Admittedly, he's a relatively extreme case, but he's far from the only person in the UK who does long-distance driving on a regular basis.
It's also worth bearing in mind that this analysis doesn't take the environmental benefits into account: reduced CO2/pollutants from the exhaust and less wear on the tyres (i.e. less latex dust in the air - http://www.straightdope.com/columns/read/2661/when-the-rubber-meets-the-road-where-does-it-go). Quantifying that is far trickier, and there could be long term negative tertiary impacts. For instance, higher costs in the UK could result in work being outsourced to countries with weaker anti-pollution rules...
All told, I'm skeptical about the benefits of this sort of standalone proposal; by itself, it achieves little and potentially costs a great deal. For this sort of idea to have merit, it'd have to be part of an overarching system which reduces the overall need for individual travel and delivery of goods...
If they really want to help the economy they should consider changing the on-off accelerator that most Spanish cars seem to be equipped with for one that allows variable speeds and smooth acceleration.
Oh, and what's not been mentioned is that to encourage use of public transport the cost of local and medium distance rail fares has been cut 5%
Not that simple tho is it? If keeping the engine to its slowest speed was the only factor I'd drive everywhere in 6th gear, which gives me something around 30 something mph per 1000 revs. Trouble is that it's labouring at low engine speeds; it doesn't really start to work properly until about 1500 and is at its most efficient speed is ~2000 to 3000 rpm, like most other modern diesels. 2-3000 equates to motorway speeds in top, so it's a balancing act to keep the road speed up to an optimum that doesn't see me creating a mobile chicane but keeps the economy up to a decent level, whilst not labouring the engine and not bothering the safety partnership cameras.
About 18 months ago I switched from a fairly light weight 2-litre diesel 2003 estate to a heavier 2-litre diesel 2008 estate. My average fuel consumption has improved from 36 mpg to 42 mpg.
I don't suppose the age difference is enough to make the engines that different. I've concluded that the difference, surprisingly, is in going from a 5-speed manual to a 6-speed automatic. The automatic frequently changes gear in places where I would never have bothered. The other noticeable difference is that the automatic's consumption is much the same whether I drive at 70 or at 90 (er, not that I ever do).
Most unlikely to be a joke; it rarely is when the powers that be conceive of another scheme to pull in the fines from those unwilling to be pushed around. It's probably temporary as it's planned to be reduced to 90 as soon as the complaints have quietened down. Perhaps 65 after that ?
Everybody above is right and wrong.
Most cars in Europe are designed to produce their maximum MPG at the regulation/tested 100kmh, about 62 mph. This means the engine in top is optimised to so that it is most efficient at that speed. This is basic advertising.
Around that sort of speed is the point where aero drag starts to become much more relevant as well - as others have said drag goes up with the square of velocity. Just try sticking you hand out of the window at 50 vs 70. A big difference.
All in all its a trade off between optimum engine efficient vs speed vs how much acceleration and braking you do. So all these things are relevant, but the most relevant for the average road car, once you get above 60mph or so, is aero drag.
Nonsense
Depends on the gearing, egine type, weight and aerodynamics. Most turbo diesels will produce better fuel consumption at lower speed. Finding straight level roads to travel at a steady 35 mph for any sig. distance is another matter.
If I remember correctly my few wanderings on the highways south of the Pyrenees, everyone was already driving way above 120 anyway, so that's just a new limit to ignore... The real problem is that the limit for losing point went down from 151 to 141 km/h (if my Spanish is still remotely accurate).
the question is not if speed is good for you or if one saves some petrol why moving slowly. The question is how is it possible that we consider normal that government will decide and force us to save petrol we paid for.
If I buy a petrol, it is mine petrol, if I decide to burn it or spill it or whatever it is still my petrol and my problem. This is not recomendition or some compaign favouring conservation, this is use of police force. We save what we paid for to use or we pay fine or we go to prison. And prison part is very real indeed, just try not to pay few fines.
Why are we discussing diferencences between 65 and 68 mph and not talking about blatant take of spanish government on our basic rights, property right.
I realize it is not such news, all government try it all the time and green agenda is especially succesful, I am just shocked by the lack of oposition. Nobody is respecting the new law, but still nobody argues from principle.
When the 70mph limit was introduced the bulk of the tires on cars were dangerous at and above 80mph. Tire safety is the best argument for keeping speed limits although it doesn't take into account vehicles with better grade tires that can easily travel 100+ without a problem.
If you want a really naff fuel saving speed limit then go for the notorious 55mph limit introduced in the US in the 70s (and now, thankfully, history). Driving 60 or slower does save fuel but having a speed limit set to this figure meant that you had to power up grades and effectively ride the brakes down -- you couldn't drive the flow. Fuel savings were minimal but it was a good source of traffic ticket revenue.
We finally got back to 70 mph over here.
I see myself having two behaviors; driving a car I tend to keep to the speed limits and draft trucks (lorries) when possible.
Riding a motorcycle I just go mad.
Wind the throttle all the way round; stand on it til my eyes blur from the vibration.
That keeps me awake and you can really get there fast at 140 mph (225.3 km/h) and yes, I do know you can get there dead.
I don't do that very often anymore because I got old.
I got old.
Poor old slow John Stepp who now has the reflexes of a 30 year old.
(I am 63)
I can't risk other people.
Ah to hell with them.
(Just on occasion; just sometimes; just when no one is watching*)
*We don't have a tenth of the speed cameras over here; drive like a maniac and enjoy.)
It seems that maths in the land of Oz works differently. Up in the Northern hemisphere a 3 hour journey at 120km/hr would take you 360km. At 110km/hr it takes 3 hours 16 minutes and 22 seconds to travel the same distance (rounded to the nearest second). The extra saving from of 13 minutes 38 seconds must be some strange effect from travelling upside down.
As Ferdinand, the expert on low speeds, has pointed out, the risk of falling asleep is great with such a huge drop of speed from 120 to 110 km/h.
But there is a clever and simple solution to this problem, there often is.
Always drive as close to the car in front of you as possible.
This will assist you in not falling asleep as easily, and the nice point here is that i will also, sort of free of charge, help the driver in front of you. In addition to this, it will decrease the wind drag and save fuel for you and your king.
Also remember to use your horn a lot, an often forgotten device in the sunny part of Europe, this will also assist you very well regarding this "falling asleep" problem.
(...)Always drive as close to the car in front of you as possible.
(...)
The explains why today that nice fellow stayed about 30 cms away from my rear bumper on the motorway. He sure kept me awake, but please do keep in mind that you have to return the favour!! No free meals!!
Some fine examples of retribu...ahhem giving thanks include, but are not limited to, using lots of water on your front windshield, so you share it when large drops of water keep impacting his front windshield, and one of my favourites, barely touching the brakes so the lights get on without the car actually decreasing speed, (it does decrease a bit but it is irrelevant while he/she starts seeing braking lights on and steps on the brakes... all for the sake of staying awake of course.
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