Concrete bridge system

A concrete culvert assembly includes a set of spaced apart elongated footers, a plurality of precast concrete culvert sections supported by the footers. Each concrete culvert section has an open bottom, an arch-shaped top wall and spaced apart side walls to define a passage thereunder, each of the side walls extending downward and outward from the top wall. Each of the side walls has a substantially planar inner surface and a substantially planar outer surface. First and second haunch sections each join one of the side walls to the top wall. Each side wall is tapered from top to bottom such that a thickness of each side wall decreases when moving from the top of each side wall to the bottom of each side wall. A bottom portion of each side wall has an exterior vertical flat extending upward from a horizontal bottom surface thereof.