When I was a kid, my dad would routinely point out "the old road" as he drove the family on some highway or another.
In the Columbia Gorge, the Old Road was a true classic - the Columbia River Highway, built between 1913 and 1922 as America's first Scenic Highway - but even in other areas, WPA era two-lanes had more romance than the modern, 1950s, four-lanes.
In the sumer of 1958, we took a long family car trip from Portland, Oregon, to the Philmont Boy Scout Training Center, in New Mexico, where my dad was to take a course. There & back was a scenic tour of Western National Parks and areas in between. Largely on two lane highways, some of which may have been the true, classic Route 66 - but most of which had that flavor, even if we were actually going south or north, in other states.
Less than fourteen years later, driving my own car from New Jersey to Portland in January, I chose an Interstate-20 route to avoid as much winter weather as possible, but when I now read about Route 66, I recognize that I was witnessing the last of the classic era in places, though at the time I thought it was long gone, buried under the Interstate.
Even in 1958, we had stretches of new-built Interstate, with more areas of construction. By 1972, the only place I recall being on 'the old road' was between Atlanta and Birmingham, where long stretches of two lane wound through small towns with many right-angle turns - but many stretches were on detours and shoo-flies among massive Interstate construction projects.
In 1975, riding with a friend from Fort Indiantown Gap, Pennsylvania, to Kearny, New Jersey, the "Lincoln Highway' markers along an elderly stretch of divided highway were only mildly intriguing, but when I came across a Lincoln Highway book the other day, I was more than intrigued, and immediately requested it and another from the library. A third, I had to order since neither local library system has it & I was excited enough to want one to keep on my shelf, and $10 for a used copy seemed reasonable enough, though it will be hard for it to measure up to Greetings From The Lincoln Highway: America's First Coast-to Coast Road.
Encouraged by some recent discussions of Road Trips, I found myself evaluating the Lincoln Highway in Nevada & Utah as road trip possibilities - as implausible as it might be for me to go there myself, with the medical and mental disability constraints, it is still great fun to read about and explore in maps and pictures.
In the 1960s and 1970s, most drivers were just relieved to have the ease and speed of the new Interstates, but even then, there were folks dedicated to exploring the byways and bypassed towns and scenery. Now Old Highways themselves seem to have become a minor, but nontrivial, interest area of their own.
I'm waiting for Road Trip USA: Cross-Country Adventures on America's Two-Lane Highways from the library. Maybe it will have a bibliography.
Seems like there is a lot more fun yet to be found in this topic.