Complex sentence: In April 1963, the state of Pennsylvania proposed renumbering I-80S to I-76 and I-280 to I-276 because the spurs of I-80S did not connect to I-80 in northern Pennsylvania.
Split into simpler sentences: In April 1963, the state of Pennsylvania proposed renumbering I-80S to I-76 and I-280 to I-276. This proposal was due to the fact that the spurs of I-80S did not connect to I-80 in northern Pennsylvania.