Yes, I understand, but a flat fee regardless of size of car as it now, is effectively a subsidy directly toward the development of car dependent cities. Also families don't tend to travel downtown by car on weekdays where space is a premium, those are usually single drivers going to work and often in NA, those lone drivers are often in large pickups and SUVs.

Large families taking the train have to pay roughly proportionally to the size, which is one of many reasons why many families opt for car culture. It's not those fault the options are this way but my point is that it can be changed.