Really, it should be international.
Now that I'm thinking about it, it's strange that vehicles are regulated at the state not federal level. They're a big component in interstate commerce, and therefore ought to be within the jurisdiction of Congress to regulate, even under a relatively strict reading of the Constitution.
For example vehicle window tinting laws vary wildly from state to state (and arguably they're more liberal in states that get hotter, and more restrictive in states with gang issues) so you can own a vehicle that is legally tinted in your home state, but gets ticketed when it crosses a state border.
Daylight running lights are another example, some states require them, while others do not. So you can buy a brand new vehicle which could get ticketed since it lacks DRLs.
Similarly, most people don't care about tint. Those that do but are agonized about being able to travel to other states can simply figure out the maximum allowed in the region they plan on traveling in. I guess that reaches the level of irritating, but what are the massive consequences for Joe Driver if he can't darken his windows?
Looks like they're strictest in Alaska, California, D.C., Delaware, Iowa, New York, Pennsylvania, and Rhode Island.
http://tinting-laws.com/wp-content/uploads/2013/09/tint-perc...
single choice monopolies impede progress, whether governmental or corporate. It's better to have states naturally group together than to force it with some top down measure.
So, for example, NY requires yearly safety inspections and you'll get a ticket if your inspection lapsed. But you don't have to get a safety inspection to drive in NY if your car is registered in a state that doesn't require safety inspections.
I could be mostly off base on this one.
Though some laws are so local sometimes it's impossible for an out of towner to know the local laws like going right on red is, as far as I know, illegal in NYC but legal... Everywhere else? How does someone from Texas supposed to know that?
You've pretty much picked an outlier. And I might be inclined to argue that someone from Texas trying to drive in Manhattan for the first time has other problems :-)
There are a few other things like whether you can pass on the right on an interstate and the aforementioned when headlights need to be on (though I often see this last point signed). But these are usually getting into corner cases and don't really affect how the average person has to approach driving.
Places with divergent laws make some effort to inform visitors of the divergence--you'll sometimes see electronic noticeboards saying that using your cell phone is illegal here, and sometimes permanent ones too (e.g, on entry into Virginia on interstates, you are immediately informed that radar detectors are illegal).
