Complex sentence: In the late 1990s, the Arizona Department of Transportation began widening US 93 to four lanes, in some areas building a completely new roadway; in other places, simply repaving the old highway and building two new lanes parallel to it.
Split into simpler sentences: In the late 1990s the Arizona Department of Transportation began widening US 93 to four lanes, and in some areas building a completely new roadway. In other places along the route, ADT simply repaved the old highway and built two new lanes parallel to it.