Complex sentence: The rest of the road between I-81 and PA 309 was built in the late 1990s and opened to traffic in December 1999; the entire length of the road between I-81 and PA 93 was designated PA 424 in 2000.
Split into simpler sentences: The rest of the road between I-81 and PA 309 was built in the late 1990s and opened to traffic in December 1999. The entire length of the road between I-81 and PA 93 was designated PA 424 in 2000.