A discouraging article from the New York Times:
Long before Volkswagen admitted to cheating on emissions tests for millions of cars worldwide, the automobile industry, Volkswagen included, had a well-known record of sidestepping regulation and even duping regulators.
For decades, car companies found ways to rig mileage and emissions testing data. In Europe, some automakers have taped up test cars’ doors and grilles to bolster their aerodynamics. Others have used “superlubricants” to reduce friction in the car’s engine to a degree that would be impossible in real-world driving conditions.
Automakers have even been known to make test vehicles lighter by removing the back seats.
Cheating in the United States started as soon as governments began regulating automotive emissions in the early 1970s.
The full story is here.