Speed zone alerts - sorta works. Most of my local roads in FL are accurate. Some are so accurate the alert sound at the sign. I can't say the same for the roads I travel on in WA though. The main road to my home there is 45mph and I have to be doing 55mph before I'm alerted.
RR crossings alerts - sorta works. There's a nasty RR I have to go over where I live but I don't get an alert. A second RR I cross occasionally in town had a bridge built over it several years ago but I'm alerted there. I was alerted of several RR crossings in the Finger Lakes region of NY. The RR crossing in Prattsburgh, NY is alerted to but it literally hasn't been there since the early 1960's! If the Train Depo wasn't still there you'd wonder, WTF. LOL
Speed cams alerts - can't help ya there. I have them all turned off. I also have the other alerts for school, hospitals, etc turned off.