When the LBJ Freeway opened to traffic in 1969 it was designed to carry 180,000 vehicles per day. In the 1980s, demand started to exceed capacity, and in 1987 the Texas Department of Transportation (TxDOT) initiated the I-635 Corridor Study to examine a 21-mile stretch of I-635 between I-35E and U.S. 80 east of Dallas. This effort was inconclusive, so efforts to find ways to upgrade the facility began again in 1993 with the LBJ Corridor Study. This study examined a number of roadway expansion configurations, including the addition of tolled managed lanes.
The tolled managed lane option was introduced for two reasons. Funding from gas-tax collections-the sole source of transportation revenue in the region at the time-was not adequate to meet current and expected future investment requirements. Tolled managed lanes could provide a new revenue source to help finance the project. In addition, the concept helped to manage travel demand in the corridor by charging higher tolls on the lanes as congestion levels increase.
The LBJ Corridor Study evolved into a Major Investment Study by the mid-1990s. This report examined a number of proposed design solutions to identify one that best met a set of project evaluation criteria. The outcome of this study, in late 1996, was referred to as a "Locally Preferred Alternative" (LPA). The Dallas-Fort Worth region's Metropolitan Planning Organization, the North Central Texas Council of Governments (NCTCOG), adopted the LPA into its financially constrained 20-year long-range transportation plan in December 1996.
Over the next several years, TxDOT undertook further analysis and design refinements on the managed lane concept. Environmental assessments for the segments ultimately included in the LBJ Express project were completed and approved by the Federal Highway Administration (FHWA) in January 2001, December 2002, and April 2004.