The scrubbing chemistry is also what gave away Volkswagen’s alleged cover-up. In 2013, a small non-profit group decided to compare diesel emissions from European cars, which are notoriously high, with the US versions of the same vehicles. A team led by Drew Kodjak, executive director of the International Council on Clean Transportation, worked with emissions researchers at West Virginia University to test three four-cylinder 2.0-liter diesel cars in the Los Angeles area: a Jetta, a Passat, and a BMW. Only the BMW passed.

“We felt that it would be possible to get low emissions for diesels,” Kodjak said. “You can imagine our surprise when we found two of the three vehicles had significant emissions.”

The ICCT reported its findings to the EPA and the California Air Resources Board. Regulators met with VW officials in 2014 and the automaker agreed to fix the problem with a voluntary recall. But in July 2015, CARB did some follow up testing and again the cars failed—the scrubber technology was present, but off most of the time.

How this happened is pretty neat. Michigan’s Stefanopolou says computer sensors monitored the steering column. Under normal driving conditions, the column oscillates as the driver negotiates turns. But during emissions testing, the wheels of the car move, but the steering wheel doesn’t. That seems to have have been the signal for the “defeat device” to turn the catalytic scrubber up to full power, allowing the car to pass the test.

Clever detective work catching Volkswagen in this nefarious scheme. The Guardian does the math on the potential damage:

The rigging of emissions tests may have added nearly a million tonnes of air pollution by VW cars annually – roughly the same as the UK’s combined emissions for all power stations, vehicles, industry and agriculture. According to a Guardian analysis, the 482,000 non-compliant US vehicles would have released between 10,392 and 41,571 tonnes of NOx annually at an average US mileage, rather than the 1,039 tonnes the EPA standards would imply. Scaled to the 11m global vehicles, that would mean up to 948,691 tonnes of NOx emissions annually. Western Europe’s biggest power station, Drax in the UK, emits 39,000 tonnes of NOx each year.

Now some expert should translate that into a rough number of deaths or years of human life expunged. It's tantamount to indirect murder, and it's laughable that CEO Martin Winterkorn refuses to resign. It will be fascinating to see who concocted the scheme and how it was agreed upon.

At the very least, Winterkorn and others responsible should be forced to walk naked through the streets while people shout, “Shame! Shame! Shame!” and throw fruit at them.

UPDATE: Just a few hours after I posted this Winterkorn resigned. He maintains he had no idea of this scheme, and it's quite possible that's true. It will still be interesting to see just how the scheme was concocted and how it was approved and carried out without Winterkorn's knowledge. Breakdowns are often more revealing than successes.