External costs - the costs that aren't covered by the user...
This is where it starts getting interesting (although I admit that the definition of interesting is subjective). Just as using a car isn't free for an individual, accommodating car use isn't free for society either. The costs that cars generate but that aren't paid for by the user are called external costs.
We pay for external costs in various ways. Sometimes we pay for them through States expenditure - meaning taxpayers pay. Sometimes we pay for them indirectly through their effects on the economy. Sometimes we pay for them in ways that aren't directly financial - for example social or environmental impacts, although these invariably have economic implications.
The most obvious external cost is the infrastructure needed for us to drive: