Interstate 635 is a partial loop around Dallas, Texas, in the United States between I-20 in Balch Springs and State Highway 121 at the north entrance of the Dallas-Fort Worth International Airport in Grapevine. It intersects I-35E at exits 27B–C, but does not connect with I-35W. Portions of I-635 and I-20 are collectively designated as the Lyndon B. Johnson Freeway; known locally as the LBJ Freeway, or simply LBJ. The roadway is named after Lyndon B. Johnson, the former U.S. Senator from Texas, 37th Vice President, and the 36th President of the United States. Where I-635 ends at I-20, I-20 continues the LBJ Freeway designation heading west. Because the portion of I-20 between Spur 408 to I-635 retains the same names as I-635, the two highways can be considered 3/4 of the beltway around Dallas. Together with Spur 408, a portion of Loop 12, and a portion of Interstate 35E, the Stemmons Freeway, I-635 and I-20 complete the beltway.
Route description
I-635 begins at an intersection with I-20 in southeast Dallas, and travels northward through Balch Springs into Mesquite, where it intersects U.S. Highway 80 and I-30. The route then turns to the northwest, continuing near the border between Dallas and Garland. later is takes a general westward turn as it intersects US 75 at the High Five Interchange. The section from I-35E to US 75 is one of the busiest stretches of road in the Dallas-Fort Worth Metroplex, at virtually all hours of the day and night. The route continues west, intersecting the Dallas North Tollway and its original terminus, I-35E in Farmers Branch. The freeway then continues to the northwest, intersecting the President George Bush Turnpike in Irving before arriving at its final terminus at SH 121 at the north entrance to the Dallas-Fort Worth International Airport.
History
I-635 was originally designated by the Texas Department of Transportation in 1959 as a loop around the eastern side of Dallas, connecting with I-35E to the northwest and southwest sides of the city. In January 1969, the first section to open to motorists was a section from US 75 near Hutchins to Barnes Bridge in Mesquite. In February 1970, the highway from US 75 westward to I-35E northwest of Dallas opened to traffic. The I-635 designation was truncated on December 2, 1971 when I-20 was rerouted south of Dallas, taking over of I-635's former route. The connecting section of I-20 from the west was not completed until 1978. Initially, the section between I-35E and US 80 in southeast Dallas was concurrent with I-20. When the outlet for I-20 from southeast of Dallas to Terrell was completed, the I-635 designation was removed from I-35E to its intersection with I-20. On April 1, 1968, Texas State Highway Loop 635 was designated from I-35E and I-635 to Spur 459 at the north entrance of DFW Airport. Spur 459 became part of a rerouted SH 121 on July 31, 1969. On July 31, 1974, Loop 635 was redesignated as part of I-635, and this section was opened in the 1980s.
Later changes
The High Five construction project, a rebuild of the interchange of I-635 and US 75, was opened for traffic in February 2006. This interchange carries over 500,000 vehicles per day and was built as the largest interchange in the state of Texas to handle this vehicle load.
Express project
A $2.7 billion project was started on May 16, 2011, to widen I-635 and dig subsequent high-occupancy toll lane tunnels beneath the primary roadway from I-35E to the High Five Interchange, a length of. Construction time was estimated in 2011 at five years and was completed and opened for traffic on September 10, 2015. The new freeway features tolled express lanes, known as TEXpress lanes, in between the main lanes or underneath them. The cost to drive on them fluctuates based on the current flow of traffic at the time. The project is among several billion dollar plus projects in the planning phase in and around downtown Dallas along with the rebuild of the I-35E & I-30 "Mixmaster".
