The other side of the coin: In constant dollars, the average cost of a new car from the beginning of the emissions & safety-regulation era (say, 1970..) has ab

The other side of the coin: In constant dollars, the average cost of a new car from the beginning of the emissions & safety-regulation era (say, 1970..) has about doubled. This is a nontrivial chunk of income. As a brit, you might live someplace where cars are optional. Many Americans have no such choice... Likewise, the low-hanging fruit has already mostly been picked. A new 1964.5 Ford Mustang, with the engine turned off, sitting in a garage, releases more toxins than a modern car does while traveling at highway speeds. The 90/10 rule absolutely applies, as it does to safety. We're coming close to having to install catalytic converters inside the engine itself to minimize the lightoff time, which is about the only place you can find NOx/VOC emissions to clean up nowadays. Not only were there upfront costs to recover for emissions & fuel economy, there were the knock-on effects on performance and reliability that took the better part of two decades to solve.