And noise! Not so much from cars, which are reasonably quiet these days. But trucks and motorbikes, especially, can be appallingly loud and make our cities unpleasant places to be.
The greatest sound pollution from cars is the tires noise. At low speeds this is not noticable but the faster you go the worse it is, I believe engine noise is overtaken by tire noise somewhere above 30km/h.
This sound is spread 10km in each direction from a highway, the areas which are truly spared the noise of cars are hard to find these days.
With cars, at highway speeds, you're right - but engine noise is a much more significant factor for motorcycles (some of which are absurdly loud) and heavy trucks/buses.
In built-up cities, like London, these vehicles are usually traveling at relatively low speeds anyway, so it's really engine noise that is the problem.
