The abandoned US 40 between Casey and Greenup, Illinois

In Illinois, the National Road appears to be one of the earliest roads to be improved at the dawn of the automobile era. I’ve found pavement on this road dating to the 1910s, for example. In 1913, Illinois chartered a State Highway Department and gave it funding for road construction. Interestingly, it wasn’t until 1918 that Illinois began assigning numbers to the highways it was building. If you look at the 1917 official Illinois highway map at this site, you’ll see that the map shows named Auto Trails rather than numbered highways. As Illinois made successive improvements to the National Road across the 20th century, in many places it built a new road alongside the old. That old pavement either served as a local road, or was abandoned. This makes the Illinois National Road a fascinating look back at roadbuilding materials and techniques of the early 20th century. I’ve found sections paved in brick and sections paved in concrete to be one lane wide. On a recent eastbound trip along…