If you mean I-80 on a bicycle, it is in most (if not all) locations, illegal. It is a freeway.
In case that is not a deterrant, the sections I have seen in PA have relatively reasonable shoulders... and 65 mph traffic.
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Slow Ride Cyclists of NEPA
People do not seem to realize that their opinion of the world is also a confession of character.
- Ralph Waldo Emerson