I use Shell V Power Diesel in my Euro6, as it has a blend of GTL synthetic diesel and supposedly more cleaning additives. It's more expensive, but in the belief that less soot will load the DPF. I haven't noticed any active regeneration side owning it over the last 6,000 miles. MPG has improved slightly over that time with a cleaner engine.

We could put part of the blame on high fuel taxes which has encouraged people to switch to diesel to eek more likes out of a gallon, to offset the cost. I would be no coincidence that many developed countries outside the EU happen to have better air quality levels because more people use petrol, as it's not taxed so highly.

$20? I spent £80 filling my Audi A6 with diesel on Monday night, admittedly with V-power diesel, which works out at $7 per US gallon. I can get 550-600 miles on that amount though.

If it's anything like the UK it will be the extortionate costs of car insurance that will put young people off driving and hence getting a licence. You're looking at at least £1,000 or more to be insured to drive at a young age, because of risk.

If you live in a country like the UK, where the cost of fuel is $7 per gallon, then driving a diesel becomes an attractive choice, and indeed this is a big reason why I have a diesel, because I rack up 24,000 miles year commuting. It would be so much less if I could afford to live close to work, but that would be futile, anyway as my wife commutes the same distance in the opposite direction and there are no jobs closer. This relates to a huge issue about a massive disconnect between having homes close to where people work, which is the elephant in the room when it comes to the question as to why so many people commute. It's either that or be out of work and a home, so it's a no brainer, unless of course you have the nice luxury of being within spitting distance of mass transit, or a short walk to work. Lucky for some I guess. I did myself. I used the Metro, but I had to move from where I used to live to after losing my job. Hence! No surprises that in countries where fuel is half the cost, gasoline is more popular and less polluting, locally at least. But in countries where fuel is highly taxed, you find ways of getting round it. Hence, diesel. Yes, Electric could be option, but that will have to wait before I can afford one, as my budget for car buying sits at $7k. It would also have to be something that can get me from the UK to France on road trips - 700 miles on a tank of diesel in a day and with a boot big enough for camping gear or capable of bring 100 litres or so of wine home, or seat 4 adults with luggage for trips to places such as Bruges like we did last summer. I try to do my bit though. I use V- Power Diesel nitro for its GTL blend of synthetic diesel - it's more poke and less smoke. And over 50 mpg is possible in my 2006 Audi A6 2.7TDi on long runs. Where I commute, air quality isn't an issue, so I don't have any shame at all of driving a Euro IV emission standard vehicle.

Unfortunately I don't have the luxury of living close to work because of the huge difference in housing costs. So I commute 35 miles instead. Hence , I tactically travel in early to beat the traffic and go for a nice 7-mile walk along a canal and through parkland. It's a nice way to start a day and beats doubling my commuting time sitting in rush hour traffic. I feel fit too!

The less poor will drive cars that are older that will get less mileage that more recent models. The greater cost will eat into any ability to save money for a better mileage replacement. In Europe highly taxed fuel means more people drive diesel engined vehicles, because you get much better mileage. I can get over 50 mpg (imperial) in my Audi A6 2.7 TDi Avant which makes $8 per imperial gallon easier to live with. Mind you I use V-Power diesel which is more like $9 per gallon. The petrol equivalent might manage 35mpg on a similar run. Now you have the green lobby with a vendetta against diesel - the same lobby that wanted and still want higher fuel taxes which resulted with more people resorting to diesel power. A spectacular own goal in that context. Yes we have electric vehicles now but for a person like me who likes road trips to France or to visit family and friends range still needs to improve and costs need to drop. I'm the sort of person who avoids finance and pays cash for my cars and saves money in the meantime for the next car when needed. Hence, bought my 2012 Audi for £5k four years ago and will get another good four years out of it. For that sort of money you'd be lucky to buy electric. Anyway, with PHEVs the quoted mileage is a scam unless your the sort that gets away with running on electric mode most of the time. Otherwise 100 mpg is a myth for long distances.

Be careful about increasing fuel taxes. It's no coincidence here in the UK that the massive surge in diesel ownership happened as fuel taxes increased under the fuel duty escalator to some 57p per litre. With air pollution now big issue, the idea that fuel taxes would benefit the environment has backfired badly. The highly taxed rate of fuel is THE reason I bought a diesel to keep a lid on fuel costs, as I have to commute 35 miles to work. My wife commutes 30 miles in the opposite direction, so moving is not an option. Neither are EVs, as we often need to cover greater distances. We drive to France for holidays, or parts of the UK for work, camping trips, or to see family. Remember also, fuel taxes are regressive, hitting the poorest hardest. So don't expect to see more wealthy folk ditching their SUVs in a hurry. It will put low paid people into fuel poverty, especially if they have no alternatives. The negative s outweigh the limited benefit in my view. To be cynical, it's a stealth tax and nothing more.

Is it really a good thing to invest a lot of public subsidy on something that will have a indiscernible impact in the great scheme of things. Is taking an older car off that could have a good few more years of service remaining a sustainable practice if the emergy and materials needed is going to more than offset any savings in lower fuel consumption. Sorry for being cynical but is this to benefit air quality or the auto industry? For my part I have a 16 year old car 1.8T Passat with 215,000 miles which suits my driving routines in a way that an EV cannot meet. In europe where fuel prices are acopalyptically high (in a US consumer's view), it's effecient enough for me to keep it going even though it runs on petrol (gasoline). I can get 45mpg on a good run to work even though it is rated to be 34mpg on the EU Combined Cycle, as I have looked after it and know how to drive effciently without driving like funeral director.

Thomas If I wanted a car for short journeys I would get one that is a lot older and has lost much of its depreciation already. I've always had older car that I have paid for in cash. I've had an 1997 Audi A6 2.5TDi cost £2,700 and lasted 7 years before I let it go to a good home for £200. I also have a 1999 Passat that I bought 11 years ago that cost £4,500 and could fetch a optimistic £750 if I sold it tomorrow. I still have it with 210,000 miles done and I expect to still have it when it reaches 250,000 miles. Even though fuel is £5.50 per gallon (or about a good $8 per US gallon) its a damned sight cheaper than running a LEAF and I get to go onlong roadtrips quite regularly which is a bonus, as I have friends and family in distant places.

The driver demographic will be quite narrow, mainly people who commute a regular daily milage that is well within EV range but adds up to high weekly milages and saves a lot in cost on petro-fuels. Very few people will buy an EV if they do limited milages as the little money saved in fuel will be completely wiped out by depreciation costs. Equally no-one will by an EV if driving patterns include longer even occasional road trips. So naturally the mileage of Leaf drivers will be more. That all aside, I think the biggest disincentive about the Leaf is the fact that it is ugly, but maybe that's more to do with the fact that Nissan have got into a bad habit of making ugly cars, likelwise with Renault who have been at it (uglification) for a lot longer. Look at the Juke as a good example or the Renault Vel Satis. The Tesla at least looks quite normal. I see them regularly in my neck of the woods.

People buying electric vehicles will do so for a reason: they do a lot of miles through a regular commute but comfortably within the range that an EV allows. I cannot see people buying an EV if the few miles and hence little saved in fuel is overwhelmed by the cost of depreciation, and that applies equally in Europe than it does in the US. That's why the mileage is higher. It attracts a certain driving demographic who typically drive a daily milage witin range that adds up to more than the average for the whole driving population. In short damed lies and statistics.

These are the unintended consequences of high fuel taxes.

The most realistic figure to go by when considering the European Cycle is the "combined" figure, not the "extra urban figure" which is more aligned to the best you will ever get if you drove like Miss Daisy. In my recently purchased car - a 2006 model with V6 2.7 litre Diesel engine, I can easily beat the 40.1 mpg combined claimed figure and even reach the claimed extra urban figure if I have a nice quiet flat empty road and take it nice and easy at a constant 55 mph. It may have something to do with cars having smaller engines which are tuned to maximise power delivery. Unfortunately you will never get the stated mpg figure if you have to "drive it like you stole it" to get the power it promises especially on hilly roads.

When the vehicle on front is belching out a bit of smoke then, yes you switch the recirc function. We know that already don't we. Hence isn't this a bit of an elaborate way of saying that that bears really do defecate in the woods?

HarveyD 87 Octane is not available in Europe. The lowest Octane is 89 (95 RON) Unleaded then there's premium which ranges between 97 and 99 RON depending on brand. Shell's V-Power Nitro is 99 RON I believe, as is Tesco's super unleaded - the latter being bad form mileage as ethanol has been used to provide the octane boost.

Fuel taxes can work but they need to be quite modest to avoid having an overly regressive effect on people on lower incomes. Look to the UK and similar countries in Europe and fuel prices, due to higher tax levels (60-65% of the pump price is made of taxes), is causing fuel poverty, especially for people who have to rely on their own transport to support their own lives. The majority of these people will drive cars that can achieve 40-50 mpg but they will still be screwed by the very high costs of fuel. Yet at the same time the landed gentry with a V8 petrol Range Rover will regard $10 per gallon as small change and a good thing as long as it rids the roads of the peasants. So, fuel taxes are only good if they are fair. So how about a $6 tax then? Would it be fair? I don't think so!

Has anyone thought of common sense? Keep it smooth and drive like you have no brake, within reason, if you can. On my way home up the A1 most traffic was bunched into the passing lane to a degree where staying in the inside lane guaranteed smoother and even quicker progress. The result for me was getting better than the official mileage stats because I had room, whilst others in the passing lane followed too close, braking, accelerating and braking and so on.

I have a 1999 Passat 1.8t which I have so far owned for over 8 years. It's done 177,000 miles and still goes well and I can get over 40 mpg (imperial) on long trips which is 500 miles on a tank. Just make sure it is serviced as per the book. Jettas, I can see an issue with. Made in Mexico with lower quality materials.

...news from the department of stating the bleeding obvious. Cue rises in fuel taxes with this "revalation" which was actually the reason fuel tax on diesel went up several years ago already. But with diesel having significant fuel economy advantages in a land where fuel taxes are painful the chickens are coming home to roost as a higher and higher proportion of the car fleet is being powered by diesel due to an obsession with CO2 figures. Is the answer to raise diesel prices? No, better brining down gasoline prices instead and in the meantime developing cleaner technologies. PS the worst places for air pollution by diesels incidentally seem to in areas where every vehicle apart from buses are banned. So cleaning up buses would be a good start as they make a good job at stinking out our high streets.

Along comes an unseasonal cold spell such as a cool April in the UK and people write it off as "weather". Along comes a hot spell in May with close to record temperatures and it becomes "global warming". People (of any bias)go for what ever side of the fence suits them best when making points.

Ok so here's the ultimate question.... Would you be seen using one in public?

The UNI-CUB in the first picture looks like a kettle but in the second picture it then looks like a vacuum cleaner with a seat!

@Peter I think you missed my point entirely. Lets deal with your personal issue first. I cruise at relaxed speeds: 65-70mph on motorways and dual carriageways (divided highways if you're on the other side of the pond), 55-60 mph. Contrary to your mis-reading and accusation I have no problem getting mileage that exceeds the official figure (my own are in my post above!). Also, nowhere did I say I travel at 200km/h (125 mph). It was you alleging it. Aside, it's not legal in the UK. So be very careful not to distort other peoples points to score points of your own! My second point goes back to the topic in question and the fact that automakers, under the tightening EU restrictions on CO2 emissions, are deliberately tuning their vehicles to perform optimally in the test rather than on the road. This is more the case with 'eco' models with downsized engines. In reality they tend to be underpowered. Think of trying to maintain a reasonable speed of 60mph on a motorway incline in the highest gear and you'll realise that having to change down gear is a sign that the engine is not ideally sized for the car. I also know of people who have bought (or chose in the case of company car drivers) 'eco' badged cars and regretted it. Most claim that, even by driving carefully, their fuel consumption falls well short of the official figures. Others in versions without the 'eco' tweaks find that the mileage figures claimed are more realistic and achievable.

Cars are becoming so finely equipped and tuned for economy that they are less forgiving to less economical driving styles. Hence, only the most masterful of hypermilers who know the car, its technologies and how to optimise them all at once will know how to get the high mileages (and hence lowest CO2 emissions) in a way that is employed to achieve the official test figures. For the more everyday who thinks driving regardless of style will achieve the claimed figures, they will be sorely dissapointed. Downsizing engines to a point where they are underpowered doesn't help. It encourages people to drive harder to achieve rasonable performance on the road - brisk acceleration (to overtake for example), uphill climbs etc all require significant efforts in an underpowered car which has a negative effect on fuel consumption. Cars with a more optimised engine size will have better torque levels which reduces to need to 'floor' it in anticipation of a hill or to get past a Sunday driver. In the past older cars were more forgiving. In fact it's obvious that many weren't tuned to get optimum mileage/CO2 figures than they do now. Hence, I routinely get more then the combined figures for both the 1997 A6 2.5TDi and 1999 1.8T Passat and can even better the extra urban figures on long smooth runs. In the Audi over 60mpg is possible, even at 70mph and 45 mpg is possible in the Passat at 55-60mph. Given the shortcomings, particularly with so called 'eco' models, my next car will be one that has a engine that is optimally sized for the weight of the car so that it avoid the issues related to underpowered engines. To this end, it would be useful for a study to compare bhp and torque per ton with mpg per ton to give us a better idea where that sweet spot is in finding an optimum engine size. Engines that are too big and too small affect real world efficiency. Getting it optimally right is key.