Almost immediately. Everyone following the speed limit would instantly enrage enough drivers that we'd be in The Purge territory.

Seriously though? I'm not sure if would. There'd be some unhappy executives, directors, and eventually shareholders but that's about it.

Considering how much the US relies on undocumented immigrants and prison labor (read slave labor), the US would certainly hurt. There's plenty more stuff to consider as well that would likely add to a collapse, but this is the biggest impact I can think of.

😮‍💨 you’ll get a gaslight red scare

People need to be historicallly conscious to effectively react when the state redecides to carpet your bloc.