When 2 independent clauses are incorrectly joined by a comma to make a sentence.
Ex: I went to the mall, Brad was there.
Correct way would be. I went to the mall. Brad was there. OR I went to the mall, and Brad was there.
People wanted the bridge built because it would be good for business. people wanted the bridge built because it would be the longest bridge. people wanted the bridge built because it would not cost very much.