Complex sentence: The current SR 253 was established in the late 1980s, but existed in an earlier form in the Medina vicinity from the early 1920s until the late 1950s.
Split into simpler sentences: The current SR 253 was established in the late 1980s. However, an earlier version of the highway existed in the Medina vicinity from the early 1920s until the late 1950s.