It's hard to organize the states to do anything collectively. Mostly, some important member of their legislator just says "Oh, our left lane law should be X", and that proceeds in a haphazard fashion until we're here. Of course, the feds have, in the past 25 years, adopted a tactic of threatening to revoke funding unless the states pass some piece of legislation or another. But it's such a blatant violation of state sovereignty that they've usually only done so in "Think of the children!" issues, like the drinking age and sex offender laws.
Really, the US is so huge now you could compare us to the European Union anyway*, and while it would make sense for California or the UK to pass one law that's mandatory for their entire jurisdiction, it would be a lot more controversial the EU or the US feds to do the same thing. And I doubt you would ever support giving the EU parliament power enough to do so, so it's not surprising that the US finds this difficult to organize.
*Of course, EU countries typically have thousands of years of history, there are less of them, and there are five EU countries bigger than any state - very minor differences, obviously.