Perfect - thank you!
Interesting that there was a huge build of highways going on in the 70s.
The aeriel view of the spot for 1983 shows the overpass so it was in place by 1983. No earlier date available that shows it.
But, if you select the topographical map for 1971 ... the interstate didn't exist there. Next available year is 1987 and it did exist. I know in my parts, the highways came first in the 70s with the crossroads used as on/offs ... the on'off ramps and overpasses were added on later. It was done that way to speed up their construction and get people "mobile". These days when new highway is built it seems to be built with highway and ramps done at the same time unlike back then.
So, still no way to know.