A ticket to greener driving?

ENVIRONMENTALLY CONSCIOUS: Madrid, in its attempts to cut air pollution, has hit upon a novel idea

Madrid, in its attempts to cut air pollution, has hit upon a novel idea — smart parking meters that can automatically adjust their hourly rates. 

How much a driver will need to pay to park their car is based on the vehicle's emissions and fuel consumption — so a Nissan Leaf driver will be financially rewarded with cut-price rates while a Ferrari or Range Rover owner might want to consider taking the metro instead and leaving the car at home.