Automaker Rankings Revisited—Does Volkswagen Now Have the “Dirtiest Tailpipe”?

, senior vehicles analyst | October 13, 2015, 3:54 pm EDT
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Last year, we released our semi-regular report card on the auto industry, the Automaker Rankings, where Volkswagen tied for 3rd place behind Hyundai-Kia and Honda. However, the astounding news this month around VW’s diesel vehicles is not only a black eye on the company—it also calls into question just how “green” the VW fleet truly is. We’ve received a lot of questions about the impact this scandal has on their environmental performance, so I’d like to take the opportunity to address some of those questions.

Just how much pollution did VW’s vehicles really emit?

It’s a little difficult to assess the full extent of environmental damage all of the VW vehicles have caused given the limited data available thus far and the array of diesel vehicles affected. However, the vehicles that were tested have the exact same engines and emissions strategies used by the vehicles covered in our Automaker Rankings (from the 2013 model year), so we can reasonably extrapolate these results.

Using the data from on-road tests meant to represent “city” and “highway” driving, our assessment is that on average the 2013 Jetta, Golf, Beetle, and Audi A3 had on-road emissions of nitrogen oxides (NOx) of 1.9 grams per mile (±0.7)—this is more than 25 times the allowable limit. The 2013 Passat had emissions of 1.0 grams per miles (±0.3), about 15 times the allowable limit.

For context, this adjustment means that the fleet of all-new vehicles sold in the US in 2013 emits about 8 percent more smog-forming pollution from the tailpipe than previously estimated, with Volkswagen’s diesel vehicles making up 8 percent of all smog-forming tailpipe emissions despite just 0.7 percent of overall sales (smog-forming pollutants include not just NOx but also volatile organic compounds, which are typically emitted at higher levels in gasoline-powered vehicles). That means Volkswagen’s vehicles have been emitting far more than their fair share of these tailpipe emissions that contribute to smog and are linked to increases in hospitalizations and emergency room visits and even premature death.

Does the “defeat device” have an impact on fuel economy?

Given the limited data, it is difficult to say exactly what impact Volkswagen’s deception has on fuel economy, and even more difficult to say what would happen to the fuel economy of these vehicles with any sort of “fix” as they begin to recall these vehicles.

Looking at the data available, the Jetta Sportwagen reproduced its fuel economy label values in on-road performance, almost precisely and well within error. However, the Passat performed slightly below its label value in the on-road tests compared to its fuel economy label, though this discrepancy was not statistically significant. Therefore, while it is certainly possible and even perhaps likely that the “defeat device” may have resulted in inaccurate fuel economy testing, based on the limited available data we cannot say that there is any statistically significant impact on fuel economy. It’s also possible that once the defeat device is corrected, fuel economy performance of these vehicles could change. Without further information available, we’ve left the fuel economy values for 2013 VW’s unchanged.

Revising Volkswagen’s smog score to reflect the real on-road emissions of its diesel fleet shifts its score from 92.6 up to 114.8, tying it with Chrysler for the “dirtiest tailpipe” in the industry. (For reference, 100.0 represents the industry average.)

Revising Volkswagen’s smog score to reflect the real on-road emissions of its diesel fleet shifts its score from 92.6 up to 114.8, tying it with Chrysler for the “dirtiest tailpipe” in the industry. (For reference, 100.0 represents the industry average.)

How does this affect the Automaker Rankings?

Adjusting for the on-road performance of Volkswagen’s diesel vehicles, Volkswagen’s score for smog-forming emissions increases by nearly 50 percent, from 93.1 up to 136.0. For context, this smog score is actually worse than the average 2005 vehicle!

Correcting Volkswagen’s smog score takes them from an overall 3-way tie for third place (with Toyota and Nissan) all the way down to a tie for seventh place with Chrysler. In other words, Chrysler now has company at the bottom—Volkswagen and Chrysler have the dirtiest tailpipes in the industry.

What does Volkswagen need to do now?

We have already heard from the CEO of Volkswagen America that there will need to be both software and hardware upgrades to the vehicles already sold in order for them to meet emissions regulations, and in the coming year they will begin a recall process to fix the issue. But what about new vehicles?

As Volkswagen looks to clean up both its image and its vehicle fleet, I urge them to examine the recommendation I made last year in our Automaker Rankings, which perhaps is even more true today: “[Volkswagen’s] diesel offerings offer only a small improvement over gasoline versions in global warming emissions. The company could do much more to reduce emissions from its overall fleet by promoting cleaner vehicles such as the Jetta Hybrid and new plug-in electric models such as the e-Golf.”

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