That is a good question. I thought 'rails to trails' dated to the '70s but a quick website check shoes '86.
I would think any bicycle related infrastructure from the '70s might be a result of the big "gas crunch" of '73/74 and resultant bike commuting.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk