When discussing what looked like a bus lane camera, James Barlow, author of Bristol's second best web site, noted that it was a watchman. More research was called for.
The watchman series of cameras include ANPR, 3G data modem, high-resolution video camera and a local hard disk drive capable of storing number plates (2 million, they say), and video shorts. If you are speeding, they actually get a video. They can also do bus-lane violation checking, which may worry the Peugeot 307 seen doing exactly that. To verify that a car shouldn't be in there it is not enough to say "is it a car"; you need to check it isn't a taxi or minicab. The Association of British Drivers have a list of proposed allowed vehicles, including lifeboat crews. Before sending a ticket to the '307 driver, the council will have to verify that the drivers/passengers were not on a lifeboat callout, on their way to Bristol docks.
The Watchman is not designed for simple speed-traps; it is a monitoring tool. It looks like it may be able to measure traffic numbers and all vehicle speeds, which could be used for datamining. As it is not currently part of the national ANPR network used to monitor and log all motorway traffic "for homeland security", this may be data we could get hold of.
The camera comes with software that sends polite notes warning drivers of their behaviour; warning notes. Their purpose is to remind without penalising. If you get a ticket, you have to pay, the insurance company ups their charges, and you may get disqualified. If you get a polite note, you can ignore it, unless eventually you start to get tickets.
Will it work? The device itself can find out. Start by monitoring peak traffic speeds before the notes begin being sent out, and their registration numbers. Then start sending notes out, and see if peak speeding speeds drop -or if the previously noted vehicles get seen repeatedly. Again, this could be a simple datamining exercise.
The sales brochure implies the cameras can be set to look for specific vehicles; download a number in and the camera will send an alert out when a specific car is seen. With a hard disk, you've got room to store a lot of numbers to search through.
Security wise, the over-sturdy mounting point is probably designed to resist a truck driving into them and getting away. You can still drive a truck into them, but it will leave noticeable damage on your vehicle. The manufacturers are proud of their security measures, though they also give away the windows software needed to connect to the cameras. The attack points for this devices are no longer the yellow box, they are the network. The camera will have a mobile phone number and a password to guess; the computers used to access it will have to stay up to date with Windows monthly OS patches or they become a target in their own right. That's the problem with networked applications: you think your device has just discovered the Internet, but in reality, the Internet has just discovered your device.