The Grand Parkway and US 290 Interchange is a critical component of Segment E of SH 99, a 180+ mile circumferential roadway commonly referred to as the Grand Parkway. Segment E is a 15.2-mile, 4-lane, controlled access toll road with intermittent frontage roads through Harris County, from IH 10 (West) to US 290 (Northwest Freeway).

Costello was selected to design the Eastbound-Southbound (EB-SB) direct connector and the SB Mound Road overpass for the interchange. The 4,250 ft. EB-SB direct connector included steel and concrete superstructure. The SB Mound Road overpass was over 300 feet long and included provisions for ultimate expansion to five lanes of traffic. Costello was responsible for structural analysis and detailing of continuous curved trapezoidal steel box girders, pre-stressed concrete U-beams, inverted-T cap beams, and drilled shaft foundations. Portions of the EB-SB direct connector were designed for future depressed frontage roads along US 290. All bridge design conforms to the AASHTO LRFD Specifications. Costello also coordinated with other Project Team Members and the Program Management Consultant.