The problem with gravel roads is that after a heavy rain a lot of potholes appear and some of them can be pretty big, it's relatively ok during the day travel, but driving at night will most certainly cause a lot of car damage and accidents in a long run.
You're right. But the cost is still lower than fixing potholes in asphalt due to wear & tear, freezing and thawing, and slippery ice is less of a problem too.
Not surprisingly, most Iowa folks are good drivers in bad weather. Generally it's avoided altogether. When it has to be done, most people are smart enough to slow down and be careful, or pull over and wait it out. There will still be accidents, but less cars slide off icy gravel roads since they seldom exist.
No he didn't say the total cost is lower, he said one side is lower and one higher. He was completely ambiguous (and I have no additional knowledge to add) about which cost changed more.
The political cost of accidents and other car damage far exceeds the political cost of a diffuse tax burden for roads which everybody generally agrees are necessary.
But wouldn't driving a road grader down the route, even once a year, be cheaper than repaving every couple of years? Just in material cost it should be cheaper, not to mention cheaper equipment (grader v. paver+dump trucks) and staffing. I fully confess, however, that I have no objective numbers.