German Car Zone

Tricksters can no longer dodge traffic through carpool lanes by using dummies or pets to fill that required extra seat. New technology developed at Loughborough University detects the number of occupants in the car through a device that measure water and blood content, meaning that Rex is no longer big enough to fill the required content and the dummy is caught out straight away (unless of course you fill it with a sufficient amount of water and blood).

The technology will initially be used in Leeds, but it is expected that other districts throughout Britain will be interested in the technology, especially considering the new camera’s potential for revenue raising. While the move is designed to reduce congestion in carpool lanes and pollution throughout the district, the cameras could also be used to measure how many people are traveling in and out of certain areas and plan traffic and emergency-situation management around this data, ultimately serving a dual purpose.
Current statistics indicate that 4 out of 5 cars in Britain’s cities during rush hour have a single occupant, and the new camera may encourage people to travel as groups to save time during the rush hour. Perhaps the greatest gain in terms of this technology will be people that take public transport, as the carpool lanes will no longer be clogged by people avoiding traffic by using dummies and thus allow buses to travel freely. Ultimately the effect of this technology is uncertain - it could create more traffic as previously illegal carpool lane users are forced to travel through regular traffic, but it could also reduce congestion by encouraging more people to travel in the carpool lane with legitimate occupants. Only one thing is really certain about the new cameras - the local governments will be getting even more revenue out of motorists.
http://www.motorauthority.com/news/safety/new-traffic-cameras-detect-number-of-people-inside-a-car/

I'm sure some company will come up with some type of dummy that will fool the system.

With a creative mind it's not difficult to beat the cameras. I know that folks in SoCal will do it in order to drive on them time saving carpool lanes. Just fill a blow up doll with water, some chicken blood, give it some clothes and strap it inside your car.

A pair of dead bodies in the trunk will do the trick.
Only be sure they did not loose too much blood... And change them regularly to avoid bad smell, too...

Haha. There's something I'd like to see.