I suppose both terms would be gramatically correct. If you are simply giving someone directions verbally, you could probably say off the highway. But, if you are writing it down as a school...
The Highway is the New Country radio station both the Sirius XM Radio network It is available on channel 16 on XM, channel 60 on Sirius (replacing New Country on November 12, 2008), channel 6060 on...