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A recent YouTube video features a claim that the VW Passat TDI 1.6 and similar cars have been banned by the US government, specifically because their gas mileage is too high. The purported reasoning is that if many people bought these cars, the government would lose revenue on gas taxes.

Could Volkswagen sell the Passat TDI 1.6 in the US if it wanted to? If not, what laws prohibit it? Does the US systematically ban high-gas-mileage cars?

(I find myself completely uninformed about the US auto market and vehicle regulations, but I'm also psychologically biased against the claim and so don't trust my own research very strongly.)

Mark Eichenlaub
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    I don't have references right now, but the answer is: Not exactly. The U.S. has strict emissions laws that make many high-efficiency engines (especially diesel ones) illegal to operate in the U.S. However, it's the emissions of these engines, not the efficiency, that is illegal. Compliance with U.S. emissions laws often requires reducing the efficiency for various complex reasons. – Flimzy May 07 '12 at 22:27
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    The true reasons behind these laws are matters for speculation. I think the more credible conspiracy theories relate to oil companies lobbying lawmakers in the name of "environmental protection," but with a hidden agenda of increased oil consumption, rather than a gov't goal of increasing tax revenue (the easy way to increase tax revenue is to raise taxes). But the are just that: conspiracy theories, and pretty impossible to prove. – Flimzy May 07 '12 at 22:30
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    Given how low US taxes on fuel are, I can't see the theory holding up: governments just don't make enough on the tax to make stupid laws worth it. Whether US emission laws are sensible is another issue. – matt_black May 07 '12 at 22:35
  • Volkswagen *builds* a current model Passat in Chattanooga the US. This is a different car to the European version, and is probably the main reason they don't import them. The US version offers 5 engines including a 2.0L turbo diesel, the European version offers many more engine variants and is sold all over Europe. The European market is very different, and fuel is (generally) more expensive there. – John Lyon May 08 '12 at 00:42
  • @Flimzy how does that emission law work, a quick read has me assuming cars need a *minimum* emission to be legal... – ratchet freak May 08 '12 at 01:20
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    @ratchetfreak: There are multiple laws at play, but the most recent one (apparently from CA only) limits diesel particulate matter in the exhaust. To combat this, manufacturers install DPFs (diesel particulate filter) in the exhaust line, which limits exhaust flow, which in turn limits engine output. There are other rules, too, which require more complex/less efficient engines and/or engine tuning, for the "benefit" of less/more favorable emissions. – Flimzy May 08 '12 at 02:31
  • For clarification, and for the sake of anyone who wants to research this for a full answer, the relevant laws appear to be California-specific. But automakers are generally unwilling to sell two versions of a vehicle, so they will generally comply with CA laws in the entire country. In effect, therefore, CA auto emissions/safety laws are US laws. – Flimzy May 08 '12 at 02:51
  • @Flimzy: VW BlueMotion engines have **significantly lower emissions**. In fact their emissions are lower than that of hybrids. Is there a **minimum emission** requirement in CA? Seems unlikely. As for DPFs, they are standard in EU since decade or so. – vartec May 08 '12 at 11:23
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    BTW, in video comments ppl seem to compare UK mpg with US mpg without realizing that imperial gallon (4.5L) is significantly larger than US gallon (3.8L). – vartec May 08 '12 at 11:27
  • @vartec: The VW diesel engines in the U.S. have pretty low emissions, too. But since most emissions laws measure the NOx/particulate/whatever matter _per volume of emissions_, rather than per distance traveled, a vehicle that got 10,000 mpg, but put out 100,000 ppm of diesel particulate matter, would not pass emissions laws. – Flimzy May 08 '12 at 16:54
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    @Flimzy: seems ridiculous. So it seems like indeed CA laws require diesels to pollute more (CO2-wise at least). – vartec May 08 '12 at 20:01
  • @vartec: Agreed, it is very ridiculous. As the current owner of 2 VW diesel engines, and former owner of 4 other diesel engines, it's sad to me to see the available diesel technology actually being reduced and dragged down by politics, at the expense of my wallet and the environment. – Flimzy May 08 '12 at 20:20
  • @Flimzy: "matter per volume of emissions" - I'm glad to see that Tom77's answer suggests otherwise (or else I would rush to patent the idea of installing a fan that mixed the engine exhaust with fresh air before ejecting it from the muffler...) – Oddthinking May 23 '12 at 15:00
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    @Flimzy not quite. CA law here places restrictions on one type of pollutant which increase the emissions of another type of pollutant. EU law limits something else again. E.g. EU law dictates CO2 emissions which means NOx emissions increase. – jwenting May 25 '12 at 05:49
  • I wonder if this was one of the cars involved in the emissions scandal... – Andrew Grimm Feb 27 '16 at 07:12

1 Answers1

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There is no law in the US that bans high gas mileage cars. In fact under Corporate Average Fuel Economy (CAFE) regulations manufacturers are fined for producing low gas mileage cars.

There are however regulations that place strict limits on the emissions produced by cars (note - Californian regulations but also used by many other states).

LEV II Exhaust Mass Emission Standards

The emissions for the VW Passat 1.6 TDI sold in the UK are as follows (source):

VOLKSWAGEN Passat Saloon 1.6 CR TDI

Converting the above data from mg/km to g/mi gives CO Emissions of 0.267 g/mi and NOx Emissions of 0.166 g/mi. So the VW Passat 1.6 TDI can not be sold in any state using the Californian regulations as it emits too much NOx.

Tom77
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    Chemical engineer here. For internal combustion engines: all other things being equal, the hotter an engine can comfortably run, the higher its efficiency. NOx is produced under conditions of high pressure and temperature. NOx emissions can be reduced by cooling the combustion temperature (reducing efficiency). California is particularly strict on NOx emissions, for some pretty good reasons; next time you're in LA, look up to see them. A lot of that brown stuff in the sky is from NOx. So it's not terribly surprising that fuel efficient cars and California don't mix well. – Jason Jun 27 '17 at 08:01