I just ran across this image of the old Dixie Terminal streetcar ramps in Cincinnati. These ramps afforded Kentucky streetcars a grade separated entrance into downtown:
The original ramps:
The replacement ramps, that were built around 1960:
The ramps were removed when the interstate highway trench was rebuilt into its current form in 1999. Kentucky buses now use a different bridge and make a circuitous lap around downtown. It's a far slower setup from the bus company's perspective, but flimsily justified by the argument that the buses come closer to more people. In the past, the Kenton and Boone County streetcars and buses did not operate on the streets of Ohio at all - only to and from the terminal building. Meanwhile, streetcars and buses from Campbell County always used a different bridge and did operate on the DT Cincinnati streets.
There was no law preventing Kentucky streetcars and buses from operating in Ohio, but after Cincinnati Transit became SORTA, there was a law preventing Ohio buses from picking up or dropping off passengers in Kentucky. The buses, however, could travel
through Kentucky and back into Ohio without stopping, which several actually do:
Here is a short documentary on the Dixie Terminal building:
https://www.youtube.com/watch?v=lYFUJR5P05Q