Interstate 345 overlays the southernmost section of U.S. 75 along the Central Expressway between Downtown and Cle Elum in Dallas. The route is unmarked, with U.S. 75 signed alone on the mostly elevated route between IH 30 / IH 45 and State Spur 366 (Woodall Rogers Freeway).
Exits along IH 345 extend the IH 45 numbering system northward to SS 366 (Woodall Rogers Freeway). They reset at the exchange with Woodall Rodgers Freeway, which is Exit 1 along U.S. 75 (Central Expressway) southbound.1
Following a feasibility study by the Texas Department of Transportation (TxDOT) started in 2019, five plans were evaluated for addressing the elevated freeway along IH 345/U.S. 75 built in 1973. The hybrid plan was selected. It keeps IH 345 above IH 30 and then lowers the freeway by around 65 feet while reconnecting the street grid linking Downtown Dallas and Deep Ellum. The freeway will ascend to connect with U.S. 75 at the present grade. Other options included removing the highway altogether, fully building it below grade, elevating IH 345 onto a narrow footprint, or maintaining the existing roadway.
If the plan is fully approved, construction could potentially start in 2027.
IH 345 was built in conjunction with the IH 45 / Central Expressway project in the 1970s.2 The designation was approved by the American Association of State Highway Officials (AASHO) on June 30, 1970.