[swolios]

Iowa has over 68,000 miles of gravel roads, something like 60% of the state's roads.

"Offroad" is 60% of the state 50+% of the year

This could be said anywhere with snow, by time the DOT repairs the frost heave after winter its winter again.

[Mawr]

Packed gravel is not "offroad", it's just a normal, flat road. Snow makes no difference either, obviously. You'd need to have quite a lot of snowfall to make travel in a regular car hard to impossible.