I can thing of several on-ramps, mostly built back in the day, that could use this. I'm guessing these are relatively low-tech & easy to install.
"One of the largest threats to that safety is wrong way crashes. When wrong way crashes happen, they are often fatal."
More...
https://portal.ct.gov/DOT/Traffic-Engineering/Wrong-Way-Driver-Home
They're not free- but maybe confusing intersections could use these.