[cjameskeller]

As someone who lives in a region with gravel/"dirt" roads, I often wonder how they compare to paved roads in terms of overall effect (possibly more fuel usage, but not, itself, made from hydrocarbons; fuel usage associated with maintenance, etc.) and what the relative health effect of the rock-dust is compared with the tar-dust/gases...

[istjohn]

Silicosis is no joke, and I imagine tires wear much faster, leaving toxic dust behind, so my bet would be on gravel roads being worse.

[elmomle]

Though presumably gravel roads limit development, keeping car traffic minimal.