Arthur T Knackerbracket has found the following story:
Among many things that former head of the EPA Scott Pruitt did during his time at the agency was to cease enforcement of emissions standards for so-called "Glider" trucks. Gliders are new heavy truck chassis that have older, less technologically advanced and emissions-compliant engines installed into them.
The Obama administration sought to close the loopholes that allow gliders to be built and sold in significant numbers in an effort to curb their pollution but Pruitt opted to toss that aside in the name of business. We've covered the glider situation in the past, but the big news is that the new acting head of the EPA, a former coal lobbyist, has moved to reinstate the Obama regulations after a court insisted that they be enforced once again.
[...] Many trucking fleets like gliders because they are often cheaper to maintain and run than modern trucks, but the amount of pollutants that they emit can be hundreds of times more than the federal standards would allow. The laws that permitted gliders to be built in the first place were designed primarily to reduce the number of wrecked trucks going into scrap yards, instead giving their engines new homes. That kind of backfired.
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(Score: 4, Interesting) by bob_super on Sunday July 29 2018, @05:23AM
You could get a 40MPG car three decades ago. But the exhaust was a hell of a lot nastier than the 35mpg car in my driveway.
Not the US, but look at the evolution of EU emission standards, which most engines worldwide have to keep in mind : https://en.wikipedia.org/wiki/European_emission_standards [wikipedia.org]
Also, because I'm not gonna bother to answer Runaway directly: Yes, you do still see many trucks blowing thick dark clouds bigger than the truck itself, at every single traffic light. When I lived in Chicago, that was almost a daily sight on my commute.