The DLC and NRVC: How States Know Where You've Been
The way tickets themselves actually follow you are results of the Driver License Compact and the Non-Resident Violator Compact. They are agreements between some states, but both will soon get replaced by the Driver License Agreement.
All three of those items are products of the American Association of Motor Vehicle Administrators, which is "a tax-exempt, nonprofit organization developing model programs in motor vehicle administration, law enforcement and highway safety." Think of it as a treaty organization for state bodies that deal with licensing and motor vehicle laws, with the aim of making laws, and especially punishments, more uniform across state lines.
Yet, while the AAMVA can form policy on issues such as tinted windows and laws against radar and laser detectors, it is up to an individual state to ratify and join any provision. Having been around since 1933, the body's goal now is "one driver, one license, one record."
Unlike the NDR, which merely notifies a state to tell you to address a problem elsewhere, the DLC effectively makes a violation in another state the equivalent of a violation in your home state.
To go back to the Pennsylvania and Florida example, if you get a ticket in Florida, the Pennsylvania DOT will assess points to your PA license. If your driving privileges are suspended in Florida, then Pennsylvania will suspend your license. The NDR only requires Pennsylvania to hold back your driving rights until you address the matter in Florida, whereas the DLC makes you pay the price for your violations in Florida no matter where you are.
The NRVC works in the same manner, but in being less onerous, it resides somewhere between the DLC and NDR. If you get a ticket in another state and don't pay it, your home state will suspend your license until you handle the issue in the other state. However, your home state will not issue points and penalties on your license, as is the case with the DLC. On the other hand, if your home state isn't a member of the NRVC and you get pulled over somewhere else, you might be forced immediately to post bond before you can drive again.
Naturally, this being a voluntary treaty organization, there are loopholes.
Not all states are members of the DLC or NVRC: Georgia, Wisconsin, Tennessee and Massachusetts aren't members of the DLC.
Wisconsin, California, Montana, Oregon, and Alaska are not a part of the NVRC. Michigan is not a member of either compact, but it does exchange information and will take action if it wishes.
How the states process violations and which violations they take into consideration also differ: some only use it for what they consider serious offenses, some have further requirements for taking action.
For instance, Kansas, Wyoming, Minnesota, Arizona, Iowa, and South Dakota won't record speeding tickets from other states unless they're ten miles per hour or more over the limit. And, most importantly, violations can only be "shared" if both states have the same violation to begin with. Get pulled over for an offense in Florida that Pennsylvania hasn't outlawed, and there's no action taken by Pennsylvania.
The DLA: The Future (And Why You Should Be Careful Going Forward)
Closing loopholes is where the Driver License Agreement comes in, and it's done with a bit of an iron fist. Any state becoming a party to the DLA submits to the fact that DLA regulations supercede any state law contrary to it. The DLA requires states to take action even if the home state doesn't have the same statute under which you were ticketed.
Say you get cited for careless driving in Colorado but your home state has no such violation; in that case, your home state will look for the closest comparable citation it could issue, such as reckless driving, and assess points and penalties based on that. And the AAMVA is working to expand the DLA internationally, not only to Canada and Mexico but to Europe, Australia, and Africa as well. In the future, when you're caught speeding to the airport in Namibia, you'll have a hell of a time trying to renew your license in Pennsylvania.
Finally, the DLA requires all member states to make all information available to member and non-member states, and that will include information like Social Security numbers.
The DLA is in its early stages - at the moment only three states are members (Connecticut, Arkansas and Massachusetts). But there are political machines in other states lobbying to join, and it has to be looked at as inevitable that the DLA will one day come into severe force in a greater part of the nation...if not the world.
No, it won't mean the end of the world, and on the bright side it will mean a closer end to really bad drivers maintaining their privileges. But the long arm of the law -- and increasingly its keen eye -- will be watching even those who amass parking tickets, not just the moving violators.
Perhaps Wez, from Mad Max: The Road Warrior, said it best: "You can run, but you can't hide."