[zozbot234]

The automobile on its own was actually far less polluting than the horse wrt. air quality. It's just that there's a whole lot more of the former than there ever was of the latter. Even wrt. climate change, it turns out that horses produce methane emissions which are far worse for the climate than carbon dioxide.

[mikelitoris]

You are immensely discounting induced demand though.

[simianwords]

induced demand is a good thing - it means there is more utility going around.