The tickets have letters and numbers on them, like a game of Bingo. We were D73. An LED display showed the numbers of the customers currently being served, and we had to wait quite a while before another D even showed up -- D68. Meanwhile, other tickets being served started with A, F, M, R, and several other letters. I was curious whether the letters actually stood for something, and I regret not asking (but I was undertandably too relieved to get my license at last to think about it). It would make sense, especially since the letters were not simply consecutive from A to G (or whatever). On the other hand, I wans't entirely sure. It could be that they mix the letters up just so you won't know how many people are in front of you. If they numbered the tickets consecutively, it could be demoralizing to find that you were 73 and they were now serving 15. You might also get angry if someone with a higher number went ahead of you. If the letters really do indicate different tasks, it would make sense that not all clerks were trained or equipped to perform all tasks. If you happened to have a task that was able to be performed by few people, such as getting a license, you might have to wait longer than someone who needed to do something simple, like renewing a registration.
Anger management is certainly an issue at the DMV. Each window has a security camera pointed at it, and I was curious enough to ask the clerk if these were for angry customers -- she assured me it was. "No matter what happens," she told me, "it's always our fault." It's true that people can be unreasonable -- very true. However, people tend to be a lot more unreasonable after they have been waiting for an hour and a half. If you've wasted that much time, you are certainly going to be disappointed if you can't even finish what you came to do, and you are going to blame the DMV. So why don't they do something about the wait?
Actually, they've done about as much as they can do, having streamlined the process quite a bit. The one thing they need now is more clerks (and possibly a bigger building), but that would cost money. Any business swamped with customers would certainly spend the money to expand; they want the extra work, and they are going to lose people if they make them wait over an hour to get served. But the government doesn't work that way. People have no choice but to go to the DMV, so there is no danger of customers fleeing elsewhere (I doubt anyone ever moves to another state because of poor DMV service.) The wait times do generate irate customers, but the people who have to deal with them are clerks, not high-ranking officials or members of the General Assembly.
Of course, the government could raise fees to finance improving DMV service. I suspect, however, that fees are high enough to provide a much better level of service. The problem is that it is very tempting for lawmakers to siphon money paid by motorists into other things, possibly transportation related, possibly not. There is no direct correlation between revenue and expenditure. This can occur in a large corporation, too, but a corporation risks losing customers. Since the DMV doesn't have to worry about this, it is easy to cut service short and spend the money elsewhere.