The case of the mystery alarm clock

If you're reading this, chances are I've complained to you in the last several weeks about how I keep waking up between 4 and 4:30am and can't get back to sleep. General consensus so far has been stress-related insomnia. So when I went to bed last night, having finished my last term paper (yay!), I expected to sleep well. Or at least better. At least past 4:30.
Well, I was wrong. I didn't sleep. But I did figure out what's been waking me up every morning! A semi truck, much like the one in this picture (only ours is bright green), has been barreling up and down our street about once an hour. At just before 4am, it was empty and headed toward the river, where Ford has some kind of storage lot for new vehicles. At 4:47am, it headed back up our street toward the highway.
The thing is, our street is residential. There are stop signs! There is a non-residential street, without stop signs, just two blocks east of us, which is where these trucks used to drive.
Here are my questions:
1) What the hell?
2) What would you call this kind of truck?
3) Who would you contact about this? The city, the company, the trucker?
4) Where do I get one of those "Not a truck route" signs?
5) Is it legal to just construct my own road block?
Sigh. I'm going on vacation for a week. Hopefully, by the time I get back, this will have stopped on its own....