Complex sentence: In November 2008, the National Transportation Safety Board determined several reasons for the bridge's collapse, including (but not limited to): faulty gusset plates, inadequate inspections, and the extra weight of heavy construction equipment combined with the weight of rush hour traffic.
Split into simpler sentences: In November 2008, the National Transportation Safety Board determined there were multiple reasons for the bridge's collapse. These reasons included but were not limited to faulty gusset plates, inadequate inspections, and the extra weight of heavy construction equipment combined with the weight of rush hour traffic.