I reckon I watched the very same season of films as a teenager in about '78 or thereabouts. Certainly Electra Glide in Blue was oart of that Bbc2 season and may well have been when I first saw blacktop. Not seen Vanishing Point, though I am aware of it.
I have seen Easy Rider, but didn't quite appeal to me that much, though not to knock it.
@jefmcg anove makes some good points which as a bloke I hadn't appreciated, but rather agree with now they're pointed out. Still a valid film reflecting the mores of the time, and that freedom may have only been there for some