Side-by-side box-beam bridges are constructed in U.S., Japan as well as in Europe. There is a recent thrust to use this bridge type because of the ability to rapidly construct them with minimal interruption to traffic. Focus of this article is the box-beam bridges built in Michigan. Current Michigan box-beam bridges utilize full-depth shear keys, a six-inch cast-in-place concrete deck and lateral posttension. Michigan bridges utilize the largest transverse posttension force magnitudes in the US. Yet, reflective deck cracking along the beam joints is continuing to be a common problem and it is identified as the leading cause of the premature deterioration process of the bridge. In order to evaluate several conflicting conclusions present in the literature, shear key condition of a decommissioned bridge was monitored. In addition, a box-beam bridge deck construction was monitored during each construction stage and shear key conditions were documented. Six-inch cast-in-place concrete bridge deck was inspected and reflective longitudinal deck cracking was documented few days after construction but before opening to traffic. Inspection data helped clarify the inconsistencies in literature and to identify the time and location of inception of cracking.