To fight against pollution, as well as loud engines, car manufacturers have been working for several years on hybrid cars, cars that switch between using a standard internal combustion engine and electric power. Toyota has been working on hybrid cars for over 15 years and its Prius is seen by many as the benchmark for hybrid vehicles. But now a new concept being developed by PSA Peugeot- Citroën - the second largest car-maker in Europe - could knock the Prius off its pedestal. The French group recently presented its revolutionary new design replaces batteries with compressed air. Under the seats a blue canister is charged with compressed air when the brakes are applied, a bit like a bicycle pump. This stored energy can then be sent back to the wheels when it is needed. It is designed to operate in three modes: internal combustion, compressed air only or a combination of the two for rapid acceleration. If the driver is constantly stopping and starting they will have a constant supply of compressed air for this process, making it ideal for those who drive in the city. In an hour's drive, the standard engine can be turned off for around 50 minutes, the rest of the time the car can run on compressed air. So fuel consumption is greatly reduced," said Guillaume Faury, Director of Research and Development at PSA Peugeot- Citroën. Fuel consumption falls to 2.9 litres per 100 km, against an average of 6 litres for standard cars today. The car can only drive a few hundred metres on stored energy but the canister takes just 10 seconds to replenish as the car slows down. PSA Peugeot-Citroën plans to start fitting the package to some of its cars in 2016, and will also be licensing the technology to other manufacturers. More about: Car industry, Fuel, Renewable energies