Something that I had not realized KYTC had released was their project archives, which can be found at https://maps.kytc.ky.gov/projectarchives/
I'm looking through one set of plans for I-64's 1967 construction in Rowan County and interestingly the highway only had 10' lanes with 4' shoulders (at least from the typical section diagram?).
The Project Archives has been around for a while--2009, perhaps?--but I last worked with it in detail circa 2013. Are projects from the 2000's or later showing up? That was largely not the case back then.