Road Archaeology, part 1 #

While on road trips I notice sometimes there are places where a road will deviate from the path I expect it to take. I take a note of it and then investigate what happened there. Usually there's some geography or history involved. Take I-5 in Northern California for example. There's a straight segment from Dunnigan CA to Williams CA:

Map of I-5 between Dunnigan CA and Williams CA