In 1916, Emily Post published her book about driving across America. Yes, that Emily Post, the society maven who invented the modern etiquette column. Before she started telling us all how to behave, she wrote “By Motor to the Golden Gate,” which is still worth reading more than a hundred years later. Not just because Post is a delightful writer with a keen ear for the telling vignette, but because her book sheds light on an issue that’s on everyone’s minds these days: infrastructure, and why we can’t seem to build it any more.