| Archive for Downsizer For an ethical approach to consumption |
| Jonnyboy |
Speed limitsThere's a lot of talk about taxing motorists to fund this that and the other. I've got a simple no cost recommendation.Reduce the national speed limit to 55mph. Three main benefits. 1. reduced fuel consumption 2. Reduced congestion. 3. Improved road safety Together these will save motorists money and save money in the economy. The downside is reduced taxation income for the government, but if they are serious about environmental changes it shouldn't be a worry. Am I in need of a stoat? |
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| Chez |
I have voted yes, but I may need some dried stoat pills too.
You'd have to make public transport cheaper - not much fun doing long journeys at 55mph, even with a good selection of Country music on the stereo. |
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| Northern_Lad |
Re: Speed limits
Yes
Most cars are designed to be at their most efficient at around 60-65. Fixing limitors so they can't be driven ove 80mph (10mph wiggle room for safe overtaking) would be sensible though. |
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| Jonnyboy |
Re: Speed limits
Really, I thought it was 55mph hence that figure being used. If it is in the region of 60-65 then I'd be happy to suggest a limit of 60 instead. |
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| Treacodactyl |
Re: Speed limits
In many places in the South East the speed limits are being changed to 50mph or less. My two nearest 'national' limit roads have changed from 60 to 40 and from 70 for cars down to 50 in the last couple of years. Not that many people stick to it and those that do tend to find an idiot stuck up their a***. Of course the usual problems with the huge numbers of people who get round speeding tickets would also need to be solved first IMO. |
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| Northern_Lad |
Re: Speed limits
Whilst a car will do 55 in top gear (generalisation, I know) there's more strain on it then when the revs are higher. So, you'd gain on the fuel economy but loose out by having to re-build your engine more often. Anyway, it's fine for you - it only takes 10 minutes to get anywhere in your country. Pitty the poor sods who live in London - it'd take them hours longer to reach civilisation. |
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| vegplot |
Being hit at 55mph isn't likely to be any less lethal than 70 so alone I don't think it's helpful but you are more as a passenger to survice and impact at the lower speed.
I'm not sure it does anything to help reduce congestions as that's a factor of density rather than speed and fast roads don't tend to be congested (M25  ).
Fuel economy, there is some merit it but a study in the US showed it only saved about 1% whether the same would be true here is another thing. I'd like to see a move to encourage smaller, more fuel efficient cars but I wouldn't like to drive one at 55mph from one end of the country to the other. |
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| Jonnyboy |
Just found this. |
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| Rob R |
The speed limit should be set by tractors, thereby reducing another traffic problem. | ||||||
| vegplot |
Re: Speed limits
I will vary from car to car but I wouldn't expect efficiency to be outside the 55-65 range. Having said that, you've introduced a top end speed (as a topic), what about a minimum speed. If 56mph is the most efficient why do we see so many cars toodling along at 40mph or less? I suspect you'd have as much to gain, if not more, by introducing a minimum speed limit. |
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| Jonnyboy |
Re: Speed limits
Is that the case? peak torque for most engines comes lower down the rev range than peak horse power. Plus any doing less RPM surely reduces less wear on the engine. Out of interest, when's the last time you rebuilt an engine, it's a non issue. 
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| vegplot |
Assuming we're still driving fossil fueled cars
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| RichardW |
A Fast track one? Top speed about 43mph specs Or this one
Richard |
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| Rob R |
No, this one  http://www.jordedecals.com/jorde/waterloo1.jpg
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| Jonnyboy |
Re: Speed limits
Off topic, but that's often down to the police not following their own procedures on calibration etc. Probably loads more people could get away with it if they had the money to defend their case. But the system relies on people accepting guilt and paying up. |
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| JB |
I vote yes but with the proviso that I would reduce non motorway speed limits. Motorways are already the safest roads we have so the safety argument is less persuasive and the optimum speed for cars is not necessarily as low as 55mph, while traffic on motorways should not be accelerating and decelarating too much so the relative fuel saving is less (I suspect the fuel saving is much greater if the speed limit is reduced on a standard A road from 60 to 50 than by reducing the motorway speed limit from 70 tp 60) | ||||||
| Barefoot Andrew |
In and around Nottingham people seem very good at sticking to the speed limit, unusually so. Why? Because of widespread usage of average speed calculating cameras with number plate recognition. If the speed limit were dropped to 55mph, the entire nation would need to be networked with these, or limiters to vehicles fitted, because it would otherwise be ignored.
In an ideal world I'd prefer to see technology used to make engines develop more power for less fuel and less emission, and to take control of some elements of vehicle control away from the driver for safety purposes. In other words, in an ideal world we'd all still retain our personal transport, it would be lean and green, but fast too. Safely. Meanwhile, back in the real world... A. |
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| Jonnyboy |
Over here we have a lot of dual carriageways with lanes and minor roads crossing them. It's deadly. |
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| Mrs Fiddlesticks |
I voted no because I think its tinkering at the edges. Those that drive irresponsibly take no notice of current speed limits so further reductions aint going to matter to them. We've quite a few A roads around here that have been dropped to 50 mph and the move was unpopular to say the least. I see some awfully risky overtaking by impatient motorists sometimes
As BA said more efficient engines are needed and more importantly to me a more efficient and intergrated public transport system is needed to make car journeys less necessary. The public already feel over watched by speed cameras which are viewed as revenue gathering rather than for safety or environmental concerns. If you proposed that as a minister Jonnyboy you'd not get away with it in the current climate of political distrust. |
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| Jonnyboy |
I'm not proposing a massive increase in the infrastructure to enforce it rather a simple reduction that would be enforced by existing measures. If the quoted figures are correct it should have a significant impact. As a test, why not try driving at a max 60mph for a week and see how further your tank of fuel gets you? |
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| Rob R |
Because that would mean speeding up 
Clarkson says we should slow down: Clarkson's top fuel saving tips |
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| Jonnyboy |
There you go, the voice of reason!
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| JB |
 A sensible article from Clarkson!
But what's the rationale behind this comment?
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| Jonnyboy |
''Fifth gear'' is a motoring show in channel 5. | ||||||
| Rob R |
With more than it's fair share of 'old' Top Gear presenters. |
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| Treacodactyl |
Re: Speed limits
I don't think it's off topic at all. Currently not enough is being done to stop people breaking the existing limits and if you stick to them you seem to be regarded as a mobile hazard. And I don't mean relying on speed cameras that'll not catch persistent offenders who drive with false plates, creatively register cars etc which is quite a high percentage. If you reduce the speedlimits even more without tackling the existing problems it's just going to be even more of a nightmare driving for people who do stick to them. |
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| orangepippin |
I did that during the first round of petrol strikes, on a regular trip from Yorkshire to Leicester. I had to make the trip, and had been unable to fill up and knew that without dire measures I would not make it back, so I drove at 50+ in the inside lane of the M1 all the way. It did make an astonishing difference. |
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| bagpuss |
you could always make dual carriageways and motorways have different max limits |
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| Rob R |
I'm quite interested in the fuel economy thing. We're always told that we should buy smaller cars to save on fuel, but I've driven a few small hire cars in my time & now I would rather pay a little bit extra & go for something a bit bigger to make economical driving easier & the overall journey cheaper than hiring a smaller one that drinks more. Much like JC's Prius race. | ||||||
| Shane |
Re: Speed limits
Only if you do it in the middle lane when the left-hand lane is empty
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| Treacodactyl |
Re: Speed limits
I don't mind about motorways, I happily drive at 65mph in the inside lane. Much slower and you end up playing chicken with the lorries which isn't my idea of fun. I was mainly thinking about single carriageways, I'm not the only one who gets a large number of other vehicles overtaking if you stick to the speed limits am I? Or do people not stick to them unless there's speed camera etc about? |
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| JB |
Re: Speed limits
If you really want to be economical I find one of the best ways is to stay on the inside lane and use the lorries as pace setters. The only problem with that is that you can spend ages staring at the back of the same lorry which makes motorway driving even more dull than it already is. |
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| cab |
Re: Speed limits
Lorries leave a nice slipstream that you can exploit at slower speeds on a bicycle; is that slipstream significantly longer at higher speeds, and does it extend far enough such that you can safely draft the bigger vehicle? And doing that, would it adversely affect the other guys fuel efficiency as much as it would improve your own? |
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| vegplot |
Re: Speed limits
The drag is already there. You are just exploiting the partial vacuum which already exists. However, the extent to which the drag area extends is small and it would be dangerous to exploit it. |
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| Gervase |
The efficiency of lorry brakes is such that any exploiting the slipstream would end up wrapped around the rear diff if the lorry braked suddenly. Not recommended if you want to add to the gene pool.
I see nowt wrong with being overtaken. I will happily drive at 55 pretty well anywhere (and in the Land Rover, anything more isn't really an option ). I tend to avoid motorways, and if people want to overtake me in single carriageways, then let them. If they sit behind me fuming because they can't go five miles an hour faster, tough sh!t.
That said, I did get a speeding ticket last year. 36mph in a 30 zone - a fair cop. 
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| RichardW |
Stop making cars that can go so fast & make them more economical at the lower speeds. Singe speed engines (fixed RPM) are much more economical than engines with large rpm ranges. Even a smaller rpm range engine is better than we have now.
Richard |
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| dpack |
pends on lots of things
i find it hard to forage at 30mph trains are fast enough for a bun and a book or observation and thought buses are fun with a crowd and hounds road transport can be needed |
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| Jonnyboy |
Put myself to the test tonight and drove home at a steady 56mph. Got a respectable 63mpg, as my place of work is close to sea level and our house is 400ft the journey included more ups than downs as well.
If traffic is light tomorrow I hope to bust 70mpg on the way to work. EDIT: everybody overtook me, apart from a truck that kept a respectable distance. |
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| JB |
But if you make a car have it's optimum fuel efficiency at a steady 50 mph then you can guarantee that people will still drive them at 70 and so get even worse fuel efficiency. |
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| vegplot |
How do you measure your mpg on such a trip? |
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| Jonnyboy |
Car has a fuel computer with two settings so I can get individual trip mpg and overall mpg. Got 70.8 on the work run this morning @ 56mph. |
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| vegplot |
It would be interesting to see the results. What is your overall mpg and what car is it? |
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| Jonnyboy |
Overall average mpg since purchase is 58.6. It's a new shape skoda fabia 1.4tdi with the 80bhp 3cyl VW engine. | ||||||
| Nick |
You forgot to mention what colour it is.
I am about to start paying for my fuel. I forsee a lot of slower journies ahead! |
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| RichardW |
I guess you missed the bit in my post about STOP making cars that CAN go to fast. Richard |
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| RichardW |
I would be interested in seeing a full tank to full tank comparison with the fuel trip meter MPG. I have a feeling that the average is a calculated figure not an actual figure.
Does sitting still with engine running give you a 0 mpg? Does coasting give you a very high mpg? I thi nk they are more of a driving style indicator than an actual acurate mpg calculator. Hope I am wrong. Richard |
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| vegplot |
You've improved your average mpg from 58.6 to 63 (7.5%) by driving carefully. To a lot of people that mybe worth getting there more quickly, not that I'm arguing that stance. If you can get 70mpg that's be a whopping 20% increase. |
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| Nick |
The ones in the Freelander, and the Alfas do give you 0, and very high, yes. They are pretty instant, and seem accurate. YMMV, of course. |
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| RichardW |
eh? |
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| Nick |
Your Mileage May Vary. Used, generally, to suggest that things may change according to local circumstances, but here, I meant it will probably vary from car to car.
HTH HAND. |
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| vegplot |
Acronyn's where would you be without them
LO F U NE MN8's, 9 I F E10 M |
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| RichardW |
I give up
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| cab |
So the slipstream never extends far enough out such that this would be safe? Shame. I asked simply 'cos I didn't know whether such would be feasible.
Sounds like a reasonable attitude. Its just not worth getting upset over such small differences in speed, yet people do 
And good on you for saying fair cop on the speeding ticket, a lot of people would be fuming mad at the 'injustice' of it. |
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| Barefoot Andrew |
So you'll not be rushing out to buy the new Audi RS6 estate then?
A. |
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| Jonnyboy |
You have an average and an instantaneous MPG. So coasting or driving downhill with no engine load may show 123mpg or ------ (above 199 mpg) whereas climbing a hill may drop it to 32mpg for the duration of the climb, hard acceleration can drop it to 8mpg! There is about a 20 second delay between instantaneous refresh, so in my opinion it is a fairly accurate reflection. Sitting in traffic does not give 0mpg. but it may do if I ever sit still for long enough! One thing to add is that we should turn our engines off more when stationary. If I expect to sit still for more than a minute i switch the engine off. |
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| vegplot |
LO F U NE MN8's, 9 I F E10 M "Hello have you any ham and eggs" To which another replies "Nein, I have eaten them" You have to imagine it's said with a heavy Germanic accent. *shuffles away quietly* |
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| RichardW |
Is it less than £2.50? I guess not then. |
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| Treacodactyl |
Personally I like to see the road ahead of me and not just the back of the vehicle in front and hope they have their wits about them, that way I have plenty of time to react to the road ahead. I'm more than happy to be overtaken, I just don't like people sitting behind me trying to force me to go faster. Of course, if I'm travelling at the speed limit then someone driving dangerously behind me isn't going to get picked up by the various speed cameras. |
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| JB |
That's why I suggest using the lorries as pacesetters rather than trying to slipstream them |
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| Jonnyboy |
Agree, I would suggest that the benefit of anticipation and reduced acceleration/braking would outweigh that of slipstreaming. | ||||||
| cab |
Not unreasonable Thats why I asked how far the slipstream extends, I mean obviously you COULD be right up to the exhaust of the lorry but thats stupid, the question reall was whether it is possible to exploit this phenomenon safely. What I've heard thus far is that it is not likely to be possible in a car.
On a bicycle, an experienced rider has to be wary of this phenomenon; it is tempting to use very often in traffic, that doesn't mean that it is always a good idea to do so. |
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| Rob R |
Yeah it is, when the exhaust of a lorry is usually between the cab & the trailer 
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| Treacodactyl |
That's also what I do although, if you allow me to be a tad selfish, the main reason has to be self preservation. |
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| James |
whats with the stoat? | ||||||
| RichardW |
Slip streams are a problem especialy when a lorry gets right up behind you & you then cant pull away because of the drag they are causing on your vehicle. Also when overtaking you can feel a "wall" of presure as you go past & on some lorries you have to widen the gap between you so you can actualy get past its that bad.
Richard |
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| vegplot |
Road kill. It tried to slip stream along with the badger. |
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| Treacodactyl |
I've not really driven on motorways much for the last few months but have just done a few trips. It's noticeable than there are a few people round here who are driving at about 55mph but most are still going as fast as before. It looks more dangerous at the moment with streams of slower moving traffic being forced into the middle lane to overtake and people not expecting such slow cars. Not as bad as a horse box doing 30mph on a motorway like there was this morning though. |