Complex sentence: In the 1950s, KY 90 was extended to include this particular road until it was rerouted to head into Cave City directly in the late 1960s/early 1970s, thereby giving the now KY 2143 the local road name Old Happy Valley Road.
Split into simpler sentences: In the 1950s, KY 90 was extended to include this particular road until it was rerouted to head into Cave City directly in the late 1960s or early 1970s. This change gave the now KY 2143 the local road name Old Happy Valley Road.