In order to stimulate more carpooling, the Government of Catalonia, Spain, is going to try a strategy that could affect people's wallets: drivers of cars occupied by more than one person will get significant savings at toll booths, and the discount system is proportional to the number of people that share a vehicle. The system will use heat sensors to determine how many people occupy the car, so purchasing a doll to save a few euros at the toll booth won't work. The first toll to test this system will be the Vallvidrera tunnels (pictured above).
The reason for this measure is to try and reduce the number of vehicles that enter the city of Barcelona. No new roads can be built there and the option of a Congestion Charge was judged too unpopular. If you remember, the city also established a plan to reduce pollution by means of reducing maximum speeds around the metro area (an idea copied from Rotterdam, in the Netherlands) The plan, which includes other measures such as the extension of the railway network and creating a network of Park & Ride systems linked to intercity buses, is due in 2012.
[Source: El Periódico de Catalunya]