I like the suggested notes, but instead of "Please see to this" or something similar, I think I would suggest something like "Perhaps you could have the sensitivity of the alarm adjusted, or leave it off when parking on <Main Thoroughfare>." That way, you're not just complaining, you're suggesting a possible solution.
Also, feel free to contact the local police for suggestions, or to call them when it's actually going off, if Neighbor seems disinclined to solve the problems themselves. And absolutely document every time it wakes you up - if you do need to get the police involved, it will help them to know exactly when and how often it happens. I keep my local police non-emergency number programmed in my cell phone for just such an occasion.
I had an occasion where someone parked a soft-top Jeep (with the top off) on the street outside my apartment building. It snowed that night, and something shorted out their alarm at 2am and it just kept going and going and going... And since I had no way of knowing if the car belonged to someone at the apartment building or the hotel across the street, I just called the police non-emergency line. I don't know if they found the owner or just pulled a fuse (which I was tempted to do myself) or what, but the noise finally stopped. Thankfully, it didn't happen again.