[caterama]

Disagree. Do you mean that vehicles gets louder because people skip maintenance? Or more stress produces more honking? An opposite effect: more financial stress means less spending on aftermarket exhaust mods means quieter traffic. Also, financial stress means less driving means less noise. Overall, I doubt you're going to find much signal in the noise!

[DaveZale]

Well, it is a perfect storm of factors. First of all lack of maintenance. Secondly, people gunning it with the gas pedal. Thirdly, lower income folks in a rush to get to a second or even third job, gunning it for reasons other than just sheer frustration.

[potato3732842]

In large parts of the country mufflers rust off periodically.

And people pay more taxes for the privilege (you don't think road salt is free do you?)