These tenants were the second house away from me, which is how loud the blasted things can be. They had two vehicles they actually used, then the old pick-up that was not a true Classic, was not restored, was just beat up and barely ran and was just parked, with, of course, the car alarm. They were at the corner of the very heavily trafficked street over there, meaning that whenever any loud truck or bike went by, the danged alarm went off. We're talking, around the clock, and they would let it run the fully cycle, the beep-beep/wah-wah/London-Bobby-siren, the works, like 45 full seconds?
The first six months they were there, I didn't know what to make of it. Then I started keeping a log -- date, time, cause -- of every time I was around. It was a single-spaced ledger that went on for 3 or 4 pages.
Then I called the cops. A total of 4 or 5 times over the next couple of months. Here's the rub: Patrol cops are usually fairly young and like loud noises such as sirens and appreciate crime-prevention measures (alarms). At first they were flummoxed about my complaint. I myself didn't know what category to label it with, just that it was some kind of nuisance, well to me since the neighbors didn't want to rock any boats. They said that noise complaints were always about loud parties or loud nightclubs, not about a crime prevention gimmick like a car alarm.
So with the first cop visits, they were sympathetic to me at first contact, but then would go talk to the dude and hear him out and he would win them over, and they would come back to me and say he was a nice dude and wanted to talk to me and had had past bad experiences with vehicles stolen from him, hence his alarm. I said there was nothing to talk about, either he was going to lower the sensitivity of the set-off or just turn it off since there was NO threat or else he wasn't, nothing to talk about.
So they told me just to keep calling until there was a history, and they were VERY impressed with my log. Finally, headquarters ran it by the D.A.'s office and the D.A. agreed that this was a Disturbing the Peace thing and that they would proceed with prosecution. Well, it never happened because the year's lease expired and they moved away.
Years after, now, I've thought that one solution might be to call the cops when the alarm goes off and do a Shirley TEMPLE dimple thing and say, "I'm SO sorry officer, but the alarm went off and I called because there MUST have been a CRIME going on!!!!!!!!!1"