Part of the Dallas beltway system, Interstate 635 (Lyndon B. Johnson Freeway) wraps around the northern and eastern side of the city. Known simply as the LBJ Freeway, IH 635 begins at Interstate 20 in Balch Springs and leads in a counterclockwise direction through Mesquite to Garland, Farmers Branch and IH 35E (Stemmons Freeway). Beyond IH 35E, IH 635 spurs 8.50 miles west through Farmers Branch, Irving and along the Coppell city line to SH 121 in the city of Grapevine. SH 121 links IH 635 with International Parkway south through Dallas-Fort Worth International Airport (DFW) and north to Lewisville.
LBJ Express lanes
A $2.6 billion project rebuilt 10.7 miles of the Lyndon B. Johnson Freeway to September 10, 2015.1 The massive project kicked off with an allocation of $50 million from the Regional Transportation Council on September 11, 2003.2 Initial plans called for twin bored tunnels below the main travel lanes of IH 635. These were cost prohibitive and eventually withdrawn from the plan. Project revisions in November 2006 replaced the tunnels with trenched roadways (later named the LBJ Canyon) utilizing space under a portion of the IH 635 general travel lanes. The cost savings allowed the project to move forward, with construction commencing in 2011.3
The LBJ Express project upgraded IH 635 between the Central Expressway (US 75) and IH 35E, with the addition of two or three tolled lanes per direction. Formally named the LBJ Express or LBJ TEXpress, the new lanes utilize variable tolling where rates increase during periods of traffic congestion along the main lanes of IH 635.
The I-635 East HOV/Express Lanes were converted from high occupancy vehicle lanes to high occupancy toll (HO/T) lanes on October 1, 2016.4 Operated by the Texas Department of Transportation (TxDOT), the express lanes allow non HOV traffic to use the lanes at a variable toll rate.
A $1.7 billion design-build project rebuilds the HOV/Express Lanes into the I-635 East TEXpress Lanes along an 11 mile long section of IH 635, from U.S. 75 (Central Expressway) to IH 30. Started in Spring 2020, work expands the freeway to ten overall general travel lanes and two managed toll lanes. Construction to late 2024 also rebuilds the multi level interchange joining IH 30/635.
DFW Connector Project
Approved for Texas Clear Lanes congestion relief funding in March 2017, work on the $370 million, I-635/SH 121 Project started in August 2018. Construction widened SH 121 through a rebuilt interchange with IH 635, added direct connectors to SH 26 and FM 2499 and expanded the Bass Pro Drive overpass.5 Included in the $1 billion DFW Connector Project, which greatly expanded 8.4 miles of SH 114 and SH 121 through Grapevine, Southlake and Irving by March 2014, construction at the west end of IH 635 reached substantial completion in August 2021.
Right of way acquisition for what would be Interstate 635 commenced in 1958 across mostly empty farm land or prairie. Construction started in March 1964 on a short segment between IH 35E and Marsh Lane by the city of Farmers Branch. This section was complete on March 23, 1967. It was quickly followed with opening of IH 635 east from Marsh Lane to U.S. 75 (Central Expressway) in August 1967.3
Work continued to build IH 635 south and east to IH 30 in November 1968, with work finished south to IH 20 by August 1970. The portion running west from Balch Springs to IH 35E in south Dallas was redesignated as IH 20 in 1971. It was completed in October 1973.3
The northwestern segment of Interstate 635 was constructed in 1981-82. Previously requested by the Texas Highway Department on March 29, 1974, Federal Highway Administration (FHWA) granted approval for the 9.5 mile long addition to IH 635 under authorization of 23 U.S.C., section 103(e)(1). The department subsequently petitioned the American Association of State Highway and Transportation Officials (AASHTO) for approval on July 31, 1974:
The U. S. Route Numbering Committee considered your Department’s application for the extension of Interstate Loop 635 northwest of Dallas. The Committee concurred in your application, subject to the understanding that eventually the western terminus of this route will be continued, so that it does, in fact, complete a loop connecting with another Interstate route.
AASHTO approved the request on November 16, 1974, with the following attached letter dated November 18, 1974:
This proposed route is located in one of the fastest growing major population centers in the nation and will connect the Interstate
Highway System with a jetport that can, and will, be utilized by the military in case of national emergency. The Dallas-Fort Worth area is fast becoming one of the major population centers in the United States. It is anticipated that more than 50% of the Dallas traffic will enter the jetport from the north using this proposed route, which by 1980 is estimated to carry 70,000 vehicles per day.