/ Motoring

What’s the truth behind car emissions claims?

Come clean on fuel claims

Our testing has found that almost all modern diesel cars exceed official emissions limits when tested in real-world conditions. We even found some hybrids breaking the limits too. So how can we trust car emissions claims?

Consumer news in 2015 didn’t get much bigger than the Volkswagen (VW) emissions scandal. The ramifications were (and still are) huge – not just for VW and the owners of affected cars, but for the whole motor industry.

Our testing is different to the official testing procedure used. It still takes place in a lab, but we use more challenging and realistic driving cycles to provide more accurate figures.

So using our lab results on over 300 cars that we’ve tested since 2012, we did a deep dive on the data. And the results were interesting.

It’s not just VW – and not just diesels either

What we found is that it’s not just VW that have been pumping out some peculiar claims. We looked back over three years’ worth of data, across all manufacturers whose cars officially comply with modern emissions regulations, known as Euro 5 or Euro 6 depending on the age of the car.

What we found was an astonishing 95% of diesel cars exceeded oxides of nitrogen (NOx) limits in our testing. The worst offender emitted 15 times more NOx as its Euro 5 engine is permitted to.

And it’s not just diesel engined cars either. We found that one in ten petrol cars produced so much NOx that they too are breaking emission limits. Now, petrol cars do also produce NOx, but this is supposed to be in such small quantities that it’s of little significance and well under the limits set. The worst offender we found emitted 15 times more NOx as its Euro 5 engine is permitted to.

Carbon monoxide

We also found two thirds of petrol cars are creating far more carbon monoxide (CO) in our tests than EU limits.

CO is different to carbon dioxide (CO2) – CO2 is harmful to the environment and your car tax is based on how much CO2 your car creates. CO on the other hand is much more harmful to human health and has no effect on car tax.

Worryingly, in our tests, two thirds of petrol cars put out more CO into the air than they’re allowed to. The worst created more than five times the amount of CO than the official limit. And it’s not just sporty or big cars that are to blame – several superminis with small capacity engines are among the top offenders. And some were so bad that they couldn’t even meet the early ‘Euro 1’ limits from 1993 – which are pretty lenient compared to modern standards.

To our surprise we also found some hybrid cars are also breaking emission laws. Testing revealed that some petrol-hybrid cars emit more CO than they’re allowed – in fact one petrol-hybrid was the 11th highest CO emitter we’ve found so far.

We’ve also identified a diesel-hybrid that produces more NOx than limits allow. And what makes this even worse is that there is no special lower limits that hybrids are held account to.

So what now?

We want you to be able to trust car makers’ fuel emission and efficiency claims. We need a stringent, independently audited test regime in the EU. It’s no coincidence that the VW scandal broke in the US, where such a test regime operates. The flawed European system allows carmakers to declare lab figures that rarely bear any relation to real-life emissions.

As a VW owner I’m currently awaiting the ‘fix’ to my car, as I’m sure thousands of you are. Last week we heard that VW has no plans to compensate VW owners in the UK, as they have in the US. But I’m curious to know whether this fix it will have any bearing on how my car performs, or on the pollution it produces in daily driving. VW has insisted that there will be no change to performance, but I’ll wait and see.

Since September, more than 78,000 people have backed our ‘Come Clean on Fuel Claims’ campaign. If you agree that more needs to be done to make car manufacturers come clean on emissions claims then back our campaign today. Also, tell us what you think about your car in our Car Survey.

So what do you think about these car emissions claims? Have you been affected at all?

*All Euro dates refer to new car registrations

phantom41 says:
25 January 2016

Pompous Which? says 95% of diesels do not meet standards and yet only list 5 as having been withdrawn from their “Best Buys” list and then – shock horror – go on to de-list 23 from the VW Group – Yah Boo. I agree with many of the previous comments about how Which? tests and their awards. Get a grip Which? list all cars that do not meet the standard. If targets have been set too high then realistic targets should be set and enforced. I am perfectly happy with my VW and have had many VW’s in the past and I certainly do not want any cars dumbed down to meet ridiculous unachievable targets. No, I do not expect compensation nor do I want it. In any case my VW is petrol and I shall never buy a smelly smokey diesel.

John says:
24 March 2017

There is a lot of two-faced opinion being put out there, which clouds the issue (pun … sorry!). The simple fact is that diesel emissions have always been toxic to us all, and continue to be so. I am delighted to see your comment about diesel; I have never had, nor ever will have, a vehicle that produces emissions that are immediately dangerous to health. As regards petrol emissions, CO2 does indeed impact on the environment but, unless one sucks on a tailpipe, will not cause such immediate and direct injury. CO, however, is poisonous but is considerably less so than the NOx gases and particulates from diesel.

VW, which produces many excellent vehicles was, nonetheless, rightly taken to task over the so-called “emissions scandal”, but no-one will ever convince me that ALL the other major manufacturers were (are) not guilty of similar actions. Only in America could the prevailing litigious attitude result in mammoth compensation claims, naturally including massive income for the legal profession. There are apparently “dumps” of diesel vehicles that have been bought back and will, no doubt, eventually be scrapped. I applaud the removal of these vehicles from the roads, even though the motive behind it was NOT on health grounds.

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Some European words about emissions testing.

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Thanks Malcolm,,,,,,,,,,,,,That made a bit of welcome reading…………According to where one stands of course

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In an earlier comment “I expect the EC to coordinate emissions limits and testing programmes………….” They do, as far as I can see, look at atmospheric pollution in the round. A search on the EC’s website might uncover the sort of information required.
For example:
http://ec.europa.eu/unitedkingdom/press/frontpage/2014/14_12_en.htm begins
“Legal proceedings have been launched against the UK for its failure to cut excessive levels of nitrogen dioxide, the Commission announced today. The toxic gas is the main pre-cursor for ground-level ozone causing major respiratory problems and leading to premature death. Most nitrogen dioxide originates in traffic fumes so city dwellers face the biggest exposure.”
and goes on
“The areas affected are: Greater London, West Midlands, Greater Manchester, West Yorkshire, Teesside, the Potteries, Hull, Southampton, Glasgow, East, South East, East Midlands, Merseyside, Yorkshire & Humberside, West Midlands and the North East.

European legislation sets limits on air pollution and the NOx limits should have been achieved by 1 January 2010. However, the EU rules offer some flexibility and extensions have been agreed with Member States who presented a credible and workable plan for meeting air quality standards within five years of the original deadline, ie by January 2015.

The UK has not presented any such plan for the zones in question.”

Later on : “In a separate move, the Commission has also asked Belgium to act on air pollution over its failure to protect the health of its citizens from fine dust (PM10) pollution. In particular, those living and working in Brussels, Ghent port zone, Antwerp (including the port zone), Flanders and Liege have been exposed to unhealthy levels of PM 10 since 2005.”

These pollution levels will not be met just by cleaner cars – other EU countries have the same vehicles but are not mentioned here. Perhaps they are all suffering pollution, or perhaps some have better strategies than the UK?

Cutting vehicle use in towns would reduce pollution substantially. But could we stomach that sort of restriction of “personal freedom” (freedom to poison others, you might think?).

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There is no need either to relax emission levels (NOx, CO, particulates, HCs) nor to accept worsened CO2 output, or performance, or fuel economy. The need for emission relaxation is a story weaved by the European motor industry to protect their sunk investment in diesel and in after-combustion treatment accessories.

My company has produced prototypes of a novel type of cylinder head which has been independently tested, academically peer-reviewed, supported by UK Tech Strategy Board funding, and patented. It delivers the best of both petrol and diesel, and beats both on economy and emissions. Not magic, just textbook thermodynamics and a revolutionary new approach to mixing and separating air and fuel flows. Incidentally, it requires no moving parts and needs only one camshaft, not two. So it is cheap to build and maintain.

Despite valiant efforts to engage UK and German car producers, we are now talking to Indian and Korean manufacturers with a view to them developing road-going demonstrators. Not sure why manufacturers closer to home are not willing even to assess the technology.


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A look at their website shows bench testing on a single cylinder version between 2000-2004 at Coventry, at Cosworth 1995-96 (which suggests building a 4 cylinder prototype for comparison with existing engines) and at Tickford in 2008 on a 2.0 litre 4 cylinder that failed during test due to a flaw in the cylinder head casting.

Seems to have been going on for a long time if the performance is as promising as given. Surely if there was full confidence in the outcome making a sound cylinder head to demonstrate its real performance would not be an obstacle.

Lets hope they attract the investors needed to decide its worth.

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A truly silly report. What next…’Shocking truth that home fuel usage goes up as you raise your thermostat levels’. How can a fuel ecomony and emission test be developed for everybodies different driving styles? ….it can’t. Very poor journalism which I wouldn’t expect from Which.

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Injecting fluid into the exhaust seems a reliable way of minimising NOx if reports are to be believed. Is this the best way forward?
Any downside – apart from remembering to top up an the extra expense?

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I understand and agree with the desire for a cleaner, healthier atmosphere. One of the contributors to a dirty atmosphere is motorised transport. A having recently retired from worked in the commercial vehicle diesel engine development business, I know how much scientific design, research and investment goes into lowering emissions from engines to meet ever tighter limits, without major penalties to fuel consumption which would hurt the vehicle owners or general public . So, I am very disappointed to find that the journalist style used by WHICH is similar to the tabloid papers i.e. big headlines, which completely mislead the readership when one reads the small print. The cars tested by WHICH used procedures which are NOT the same as the Internationally agreed standards for testing, therefore the statement “… emitted more oxides of nitrogen than limits allow” is completely misleading. You may as well say all boiled are hard by the WHICH standard of 5 minute cooking!
Without an internationally agreed new test standard for emission testing, which should include more simulation of real world driving, any independent organisation can invent a new method to test vehicles and show that the emissions and fuel consumption are not the same as the official figures.

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What, for me, would be very useful is to know is which are the 5% of diesel cars that do comply with N0x emissions? Surely this is the useful info from this investigation? A list of the worst 15, of 95% (how many in the 95%), is a journalistic puff – not the hard, useful, information we pay our subscriptions for.
So, Which?, which diesel cars should we buy?

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Colin, i agree we should see NOx emissions published. But measured on what basis? The need is to represent real life, and as has been said before, that needs a definition of what real life driving is. Otherwise figures derived from different arbitrary test regimes cannot be compared. At present the only figures officially recognised for comparison with regulations are, I believe, those measured in the laboratory-based EC’s NEDC test – out of date and recognised as very defective. There is no recognised on-the-road test yet, but the EC has just launched the “real driving emissions” test to trial; this is a road test done to a specific driving regime and will hopefully yield figures we should generally expect in practice.

This is what I understand. The Which test does not, as far as I know, follow the RDE test – if it does I would like them to tell us. Standardised testing is essential and whilst Which? should be applauded for testing fuel consumption under more realistic conditions than the NEDC, it does not yet as far as I know have any official status as far as NOx results are concerned. It just confirms what is already known – that on-the-road results for most vehicles will differ, often significantly, from lab results.

Mark says:
5 March 2016

Surely Which? should just publish the PM2.5, NO2, CO2, measurements from a standardized test.
The power source – diesel/petrol/PHEV/hybrid, does not matter.
Existing limits do not matter, there is no safe amount for PM2.5
PM2.5 is estimated to cause 432,000 premature deaths pa in the EU.
NO2 is estimated to cause 75,000 premature deaths pa in the EU.
CO does not cause many deaths, so not sure why Which? are putting so much emphasis on it.
These numbers suggest that PM2.5 should be the primary target, then NO2, then CO2, then CO ?
A quick search shows that domestic wood burning causes almost as much PM2.5 pollution as all road transport.
Surely this is an easy, low cost fix.

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Hi Mark, , I like your bit on the wood burning stoves
What about the many pellet etc burners that our oh so wise government gave incentives on to have installed and further incentives on for 20 years or whatever on a per kwh basis

Yes pollution should be pollution
You PM2.5 is dangerous, , much more so than the older black soot we could see and I’m very happy to see others take this up. . You must though look at where the increased amounts of this have all came from. . . Try telling someone to put their fire out??
We now have countless diesels with NOX reduction equipment that make more soot as a result but the increased amounts of that larger soot is then reduced in size by the DPFs to make very fine particles but the reality is that the overall amount of pollution is in my eyes not reduced
Thats in my eye’s. . I understand others may not agree or need endless evidence which like most things is too complicated to be going into
To me they have just converted one thing into another to fit the requirements and whether it’s pm10, ,pm2,5, ,nox or co they are all bad

co2 (dioxide) which I hope you refer to does not cause many deaths but CO (monoxide) does
I think Which emphasise the CO as that is what the road tax bands were based on and everything it seems comes down money or the fact that some driving relatively low NOX petrols cars are now feeling well overcharged in view of the high NOX outputs we are now aware of. . NOX of course being much more harmful

John says:
24 March 2017

Current attitudes now suggest that diesel emissions will never be acceptable, and moves are afoot to ban diesel in a number of European cities. London is (still) in Europe, but it seems the UK approach is to … raise more income by CHARGING you to take your diesel into the city! That’ll help with clean air, won’t it? All of this will doubtless render the compliance figures redundant. My experiences of diesel emissions started back in the ’70s and I still adamantly believe that diesel should have been dumped many years ago.

Mike says:
1 March 2016

Why is it that just VAG is being slated for this, we all know if they’ve done it all the other car manufacturers are also doing something similar but haven’t admitted it. They all need exposing and brought down to the same level.

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“we all know if they’ve done it all the other car manufacturers are also doing something similar but haven’t admitted it”
VAG as you call them are the only ones who “cheated”
Others may not be as clean as one would wish. . The NEDC test has and is a joke but VW used a system to deliberately pass any recognised test and then the same system simply waved bye bye to emissions controls for normal road use. .
That is why VW are being slated
I’m not even sure “slated” is the correct word. . Certainly Wave, I and others have written much on the subject and we have made loads of mention about others being less than perfect. .
Do you for one second think that if there were others VW would be keeping quiet about that, , not on your life, , If VW could shift the blame they would, ,
After all VW have sang their own praises for some time and never worried about who they trampled on on their way up so would not worry about bringing the entire house down

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While the published report is useful headline stuff, Which? should make available on its web site the results for all the cars tested, not just the selected ones shown please.

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The only “emissions limits” that cars must currently comply with are those measured during the laboratory NEDC tests. Any implication that cars “are breaking emission limits” (illegally) under on-the-road driving is incorrect; there are currently no official on-the- road tests in force nor corresponding on-the-road limits (although the RDE test is currently being trialed). It is well known that on-the-road performance figures differ significantly from the official NEDC test.

Now, before you come down on me like a ton of bricks, I am not condoning high polluting emissions. I want to see poisonous gases minimised as much as anyone. I simply want Which? to be honest and straightforward about how it portrays the results with which it seeks to influence our opinions. The facts are clear; there is no need to do more than that.

Out of interest, can Which? tell us how they measure emissions, including NOx, and what laboratories or testing agencies they use to carry out these tests.

I agree with George – all the results should be published so we can make our own minds up.

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An outline of how Which? tests cars can be found here: which.co.uk/cars/choosing-a-car/how-we-test-cars/how-we-test-mpg/ I would be interested in more details, but the same applies to much of Which? product testing. What is clear is that cars are not modified prior to testing. No taping-up the doors, over-inflating the tyres, disconnecting the alternator, etc to produce better figures.

I challenge car manufacturers to declare that they don’t modify their cars prior to testing.

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Which? test procedure is nearer to an “on-the-road” regime than the NEDC laboratory test regime, so results are not comparable. We need to standardise the “on-the-road” test so all results are comparable – the RDE should go part way towards this – and laboratory testing on the WLTP.

Car manufacturers should obey the NEDC requirements. If those requirements do not disallow switching air conditioning off, for example, or using a fully charged battery then that is a deficiency the EC needs to deal with (and has in the WLTP). However, the NEDC results do not, and were not expected to, yield the fuel consumption and emissions you would get in real life; they were designed to produce “comparative” results only between cars, and figures that could be used to check limits set under the NEDC driving profile. If all manufacturers make similar modifications then the comparability required is still achieved. Just let us not expect more from the NEDC test than it was designed to do.

I hope the WLTP produces not only camapartive results consistently, but also results near to what we will achieve in practice for “average driving” (whatever that might be). I also hope the RDE test produces real life emission results on which sensible limits can be set.

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I’ve read this a number of times and Which? do attempt to use a test regime that better represents on-the-road use. The EC’s WLTP test regime is also designed to do this, so hopefully if Which? aligns their test with the EC we will have more comparable results.
Which? says ” Every new car launched is now available with manufacturer claimed mpg (miles per gallon) figures.” and “Ever strived to match the manufacturer’s claimed mpg figures in your car and not been able to?” However let’s be clear. Manufacturers can only publish the useless figures allowed by the EC from the NEDC test. So they are not “manufacturers’ claims”, anf however hard you strive you are unlikely to get them in practice.

They say “It’s very hard to get truly repeatable and comparable results when using multiple labs.”. So how are Which?’s results likely to be more superior than anther labs? They aren’t; there will always be normal measuring discrepancies, hence comparative results. All manufacturers could never use just one laboratory; that is fanciful.

The link from Which?s site says “In our tests, 95% of diesel cars, along with 10% of petrol cars, pump out more NOx than EU limits allow. “. This is untrue. The EU limits are based on an NEDC test and that is where manufacturers results come from, Not from Which?’s test regime or the WLTP test. There are no regulatory limits for these. Hopefully there will be when the RDE (Real Driving Emissions) test is up and running – an on-the-road test.

We need clear facts and honesty in portraying them otherwise many are in danger of being mislead.

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For years we have had advertising that states something to the effect that calls from landlines cost xxx and the cost of calls from mobiles can be considerably more. Is there anything to stop responsible car manufacturers from telling us that most drivers will not come close to achieving the official fuel economy figures?

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Their adverts tell you so. The three in my weekend mag say “Official EU test figures. For comparison purposes only. Real world figures may differ”, or similar. I’d expect an independent organisation to portray the figures for what they are, and not suggest otherwise. I can make my own mind up, like many others, from the facts; I don’t need them to be distorted or misrepresented.

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The EU has instigated Real Driving Emissions (RDE) testing to get a way of determining what cars emit in normal use (as opposed to in laboratory testing), in particular NOx. The aim will be to set down limits for emissions that must not be exceeded on the road as part of type approval for new vehicles. The test, with a portable emissions analyser, will take place on normal roads – 34% urban with stops, 33% rural, 34% motorway, at typical speeds, over 90-120 minutes duration.

NTE pollutant = CF pollutant x Euro 6.
This means that the not-to-exceed (NTE) pollutant level = the Euro 6 specified level (lab test value) multiplied by a conformity value. This value will be set on the basis of the results of the first phase of the RDE trials.

“‘10. The manufacturer shall ensure that, throughout the normal life of a vehicle which is type-approved in accordance with Regulation (EC)
No 715/2007, its emissions as determined in accordance with the requirements set out in Annex IIIA to this Regulation and emitted at an RDE test performed in accordance with that Annex, shall not exceed the values set out therein. ”

I cannot see how “throughout the life of the vehicle” can sensibly be met. Surely it depends upon maintenance? Although maybe a test vehicle has to be retained and retested at intervals to check continuing compliance? But what happens if it fails?

Given this, it is a big step towards making testing (and type approval) realistic.

The full regulation is at http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32016R0427&from=EN

Perhaps an expert out there can comment?

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Now Mitsubishi admits to cheating on some models…….no cars affected have been sold in the UK apparently. You wonder at the business acumen of a company that perpetrates this kind of fraud. Surely the inevitable (they will be found out) costs in both money (company value, loss of sales) and reputational damage far outweigh any potential gains? I imagine like VW Group “lessons will be learned”?

At a news conference in Tokyo, Mitsubishi president Tetsuro Aikawa bowed in apology.

He told reporters the wrongdoing came to light because Nissan alerted it to inconsistencies in emissions data.

He said Mitsubishi’s internal probe uncovered the manipulation by staff and independent investigators had now been called in to identify those responsible.

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Nothing quite like the efforts of VW Group though
Apparently they adjusted the tyre pressures to help the mpg so it’ll not be very adverse to emissions or a big % on mpg. .Unless of course someone has thought of a way to cover something worse up which would not surprise me
The difference between the recommended tyre pressure and very high tyre pressures is an advantage in the lab for this purpose but it’s just one of the very many tricks. . .Mitsu seem to have went over the recommended pressures and admit to it , , if that’s all it is
This is what they do. . .All of them
The very light grade engine oils, , gearbox’s that use transmission fluids. . .Chain driven timing gear . . .It all add’s up

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“”The wrongdoing was intentional. It is clear the falsification was done to make the mileage look better. But why they would resort to fraud to do this is still unclear,” he (Mitsubishi Motors president) said.

The point is they deliberately went outside the allowable test parameters, it seems. The question I posed was not so much one of degree but, like VW, do not the costs of the inevitable disclosure far outweigh any potential gain? Apart from the moral issue, surely a silly way to run a business?

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Yes the wrongdoing was intentional. . .Did I say otherwise? . . It’s always intentional. . .Thats what they do. . . They fly close to the wire. . .This time they fell off the wire. . .Big Business is not gentlemanly. . .Its about sales. ..

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I suppose in the light of modern risk assessments, safety guidance, and the need for personal protective equipment in appropriate places, Japanese chiefs are no longer permitted to fall on their swords [even if they were allowed to have them in the first place]. Not much deep bowing went on in Germany, however, and – so far as I am aware – nobody has yet been shot in front of the VW executive board as a warning to the others. Corporate standards are certainly slipping around the world.

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21/4/16: Government publishes findings of diesel emissions testing programme:
“Vehicles tested in the UK programme showed no evidence of car manufacturers, apart from the VW Group, fitting devices to defeat the approved emissions test programme.”

Volkswagen has admitted rigging emissions tests in the US and Europe. We’ve repeatedly shown in other tests that car makers are claiming figures that are miles from the truth

Perhaps Which? would now make a statement that corrects what could be their easily misleading claim that “Our testing has found that almost all modern diesel cars exceed official emissions limits”. Other then VW cheats, cars do not exceed “the official limits” – the limits imposed by the EC.

This is not about whether emissions should be reduced – of course they should. This is simply about Which? providing accurate, fair and balanced information and not attempting to stir us all up with half truths. It is a responsible consumer organisation, not a tabloid. 🙁

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There is a new discussion opening up around the effect of external temperature on NOx emissions from, primarily, Euro 5 diesel engines. Apparently the way engines are managed – exhaust gas recirculation for example, EGR valve – can affect engine component life and to counteract this changes can be made dependent upon air temperature. This can then affect fuel consumption and CO2 in a positive way, but NOx negatively.

I hope that all sides involved – environmentalists, EU and UK testing agencies, ACEA (industry) will make positive and constructive contributions so we get a picture of just what is happening. Euro 6 engines – the current standard – are much less affected it seems.

At present the EU are trialing a Real Driving Emissions Test under controlled on the road conditions (as far as is possible) and we will hopefully get useful information from this that can be related to temperature. The aim is to set “real life” emissions limits where none currently exist. I wonder how far older engines will deteriorate in use – cleaning or replacing EGR valves that feed some exhaust gases back through the inlet manifold is often necessary if noticed, but not a requirement. Perhaps checking emissions and maintaining the system should become an MoT requirement?

I still maintain that, while reducing nasty emissions is clearly worthwhile, it is in our towns and cities that such reductions will have insufficient impact in protecting health. The only way is to cut down on traffic using towns and cities.

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Contributor DeeKay gave us very detailed information about the problems created by exhaust gas recirculation. The introduction of positive crankcase ventilation was a sensible move but recirculating exhaust gases is going to cause problems, sooner or later.

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As this is slightly related and just been announced it might be of interest . Sweden as we know is “getting rid ” of fossil fuel vehicles by 2030 and has just introduced a trial length of 2 Km of a main road overhead power lines . They have converted two diesel hybrid articulated lorries to run with a Pantograph mechanism connected to the top of the lorries -ie- same as a trolly bus but the trucks can continue after the end of the electric track on diesel . if successful Swedish roads could be covered in overhead tracks for large vehicles speed would be 56 MPH .

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I found that very interesting.

Pantographs would certainly be better than trolley collector poles as they can easily be lowered and raised to allow overtaking. Presumably each vehicle would carry a meter to charge for the current collected from the overhead wires. It is also a good way of recouping the additional road wear costs of heavier loads because the number of axles can be programmed into the meters and the electric motors would require more power as weights increased. A time dimension in the metering would also allow for selective road pricing in congested locations. Regenerative braking is also a possibility. I am intrigued to know how the return current is handled unless it is a two-wire system which would make for a complex pantograph – unlike a tramway or electrified railway track a highway must allow for much greater lateral movement of the vehicle which is why trolleybuses had two long poles mounted on a swivelling platform. On a tramway or railway track the return current is transferred to one of the running rails but this is not possible with a road vehicle. Perhaps they are also installing a collector strip in the road surface. Sweden has huge hydro-electric power resources so this is a sensible development there.

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Duncan / John

Thanks for this.

As regards the return current, a quick “google” showed pictures of twin parallel wires and a lorry with 2 pantographs side by side.

A bit more googling revealed a page where the voltage was quoted as 750V dc.

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Thanks Derek. I followed up your comments and read “The company (Siemens) said steering a lorry connected to the overhead lines is no different from driving a normal diesel lorry, as the active pantograph compensates for any shifts in position within the lane and automatically disconnects in the event of evasive manoeuvres or if the vehicle’s indicators are used. It said lorries using the new system, which operate as hybrid vehicles when not on the electric road, reduce energy consumption by half, as well as eliminating local emissions“.

It’s the ‘active pantograph’ that makes it possible. It’s not a pantograph in the conventional sense but a pair of beams which support bow collectors and the accompanying picture suggested that the beams might be telescopic and hydraulically powered to maintain good contact with the conductor wires.

It’s what we have been waiting for for heavy haulage and I can foresee a good case on orbital roads around towns and cities and on radial roads with heavy goods traffic. Long distance motorways might be prohibitively expensive to equip and we don’t yet enjoy an abundance of electrical power. I noted that only the inner lane was electrified with outer lanes being used by cars and smaller vehicles.