Remember Tracer...he has one and makes a daily upload to youtube. He tested a few and somewhere in his videos is his rating on the ones he tried. Last week he started on the kick to try some a new ones.

dash cam recorded this recently in Canada
some dummy passing on a double yellow line going up hill
did you notice the side of the trailer, he was carrying Hazmat too,
plus he never stopped. They are still looking for that driver.


http://www.youtube.com/watch?v=Ce9lF_9m7yQ

that is unreal hog ,we had one over here couple weeks ago wide load [a boat ]coming south down state highway 1 a truck then car following going slow whole road taking up,u see orange lights and cb talking it near midnite a semi comes down highway full speed straight into car and other truck ,2 in car dead truck in front had rear cam so proof there.both trucks and car burnt out .it dead straight highway just not the best of drugs I think.u see it on stuff news sumwer.truck crash south of sanson

We have cameras in our trucks. DriveCam is the name. It's about the size of an external speaker and it's mounted on the windshield. Shows the frontal view, and view of the driver. (In case you were talking, texting or eating etc)
From what I hear, they have sensors inside them that makes them record. If you hit a good bump or something, it records. Somehow, it saves the last 8 seconds, and records for 4 more seconds (or something like that). You're not on camera all the time, only when it's triggered. Hard braking, hitting a bump, or anything that would make the camera think the truck is in an accident, etc triggers the camera to record.
From what I understand, there are these guys that watch clips that come in, and then they send them to the safety dept of the company.

That's a brief summary of what I've heard how they work.
Here's their website..
The Driver Safety and Driver Productivity System | Driver Risk Management

That camera probably does record all the time, but only keeps the video for 8 seconds before and 4 after something happens.

As for that video in Canada, they did find the guy that caused it: Akmal Hayat accused of being trucker in near-crash video that went viral - Thunder Bay - CBC News

I bought one of the $100 one's at TA and really was surprised at how well and how much it recorded. With the unit mounted to the windshield it will 'see' just to the left and right of my fender mirrors. So in other words if a car is in front of my or moveing over it is recorded. Mine is constantly recording and just records over the old video. The bad part is that according to the directions your supposed to turn it off every night, I didn't and the battery charger went to crap. Oh well thats why they make after market chargers.