Cities deal with their cars in black and white: either all of them have equal access to an area, or none of them has. But not all cars are the same, in terms of weight for example. Lighter cars statistically consume less, pollute less, are cheaper and smaller (so they take less parking space). Sounds good in an urban context no? This presentation is the result of a master's thesis I did at the Technical University of Munich (TUM), and proposes to redesign congestion charging schemes (like the one used in London for instance) to incentivize the use of lighter vehicles at the city scale.