Interstate 635 (Texas)
Interstate 635 (I-635) is a 37-mile-long (60 km) partial loop around Dallas, Texas, in the United States between I-20 in Balch Springs and State Highway 121 (SH 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.
|Lyndon B. Johnson Freeway|
I-635 highlighted in red
|Maintained by TxDOT|
|Length||36.999 mi (59.544 km)|
|Existed||October 1, 1959–present|
|Southeast end||I-20 in Balch Springs|
| I-35E in Dallas|
US 75 in Dallas
I-30 in Mesquite
US 80 in Mesquite
|Northwest end||SH 121 / International Parkway near DFW Airport|
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 (Walton Walker Freeway), and a portion of Interstate 35E, the Stemmons Freeway, I-635 and I-20 complete the beltway.
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 (US 80) and I-30. The route then turns to the northwest, continuing near the border between Dallas and Garland. Six miles (9.7 km) 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 (Central Expressway) 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.
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 10-mile (16 km) section from US 75 to Barnes Bridge in Mesquite[clarification needed]. 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 13 miles (21 km) 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.
The High Five construction project (so called because it is five levels and rises almost 120 feet (40 m) above the lowest level), 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.
A $2.7 billion project was started on May 16, 2011, to widen I-635 and dig subsequent high-occupancy toll (HOT) lane tunnels beneath the primary roadway from I-35E to the High Five Interchange, a length of 8 miles (13 km). 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". 
|Dallas||Balch Springs||0.0||0.0||I-20 west – Fort Worth||I-20 exit 480|
|0.1||0.16||1C||I-20 east – Shreveport||Southbound exit and northbound entrance|
|2.6||4.2||2||Lake June Road|
|Mesquite||3.6||5.8||3||West Cartwright Road / Bruton Road|
|5.0||8.0||4||SH 352 (Military Parkway / Scyene Road)|
|6.6||10.6||6||US 80 – Dallas, Terrell||Signed as exits 6A (west) and 6B (east)|
|8.1||13.0||7A||Towne Centre Drive||Southbound exit and northbound entrance|
|7.5||12.1||7B||Town East Boulevard||Signed as exit 7 northbound|
|8.7||14.0||8||I-30 (US 67) – Dallas, Texarkana||Signed as exits 8A (west) and 8B (east); I-30 exits 56B-C|
|9.7||15.6||9A||Oates Drive / Galloway Avenue|
|Managed HOV Lane||Northbound exit and southbound entrance|
|Mesquite–Garland line||10.8||17.4||9B||La Prada Drive||Eastbound exit and westbound entrance|
|Garland||11.4||18.3||11A||Centerville Road / Ferguson Road|
|12.2||19.6||11B||Northwest Highway / Shiloh Road|
|13.4||21.6||12||SH 78 (Garland Road)||No direct westbound exit (signed at exit 11B)|
|Garland–Dallas line||13.9||22.4||13||Jupiter Road / Kingsley Road / Walnut Hill Lane|
|Dallas||Managed HOV Lane||Westbound exit and eastbound entrance|
|15.2||24.5||14||Plano Road / Church Road|
|16.0||25.7||15||Miller Road / Royal Lane||Access to LBJ/Skillman Station|
|16.6||26.7||16||Skillman Street / Audelia Road|
|Managed HOV Lane||Westbound exit and eastbound entrance|
|17.6||28.3||17||Forest Lane / Abrams Road|
|18.2||29.3||18A||Greenville Avenue||Signed as exit 18 westbound|
|Managed HOV Lane||Eastbound exit and westbound entrance|
|I-635 Express west to SH 289 (Preston Road) / Dallas North Tollway||Westbound exit and eastbound entrance|
|19.5||31.4||18B||TI Boulevard||No direct westbound exit (signed at exit 18), access to LBJ/Central Station|
|18.8||30.3||19A||US 75 – Dallas, McKinney||High Five Interchange; US 75 exit 21|
|20.2||32.5||20||Park Central Drive / Hillcrest Road|
|21.5||34.6||21||SH 289 (Preston Road) / Montfort Drive|
|Farmers Branch–Dallas line||22.8||36.7||22B||Dallas Parkway / Inwood Road / Montfort Drive||No direct eastbound exit (signed at exit 22D)|
|23.2||37.3||22C-D||Dallas North Tollway||Signed as exits 22C (north) and 22D (south)|
|24.1||38.8||23||Midway Road / Welch Road|
|25.2||40.6||24||Marsh Lane||No direct westbound exit (signed at exit 23)|
|25.8||41.5||25||Webb Chapel Road / Josey Lane / Denton Drive / Harry Hines Boulevard|
|Dallas||I-35E Express – Dallas, Denton||Westbound exit and eastbound entrance|
|27.8||44.7||27B-C||I-35E (US 77) – Dallas, Denton||Signed as exits 27B (north) and 27C (south); I-35E exits 440B-C|
|Farmers Branch||29.0||46.7||28||Luna Road|
|Irving||30.0||48.3||29||Pres. George Bush Tpk. north||Signed as exits 29 (north) and 30 (south) westbound and exits 29A (south) and 29B (north) eastbound|
|30.7||49.4||31||MacArthur Boulevard||Access to Las Colinas Medical Center|
|31.9||51.3||31B||Olympus Boulevard||No direct eastbound exit (signed at exit 31)|
|Coppell–Irving line||32.8||52.8||33||Belt Line Road|
|Tarrant||Grapevine||36.7||59.1||36A||SH 121 south / SH 114 – Fort Worth, DFW Airport, Dallas||Westbound exit and eastbound entrance|
|36.9||59.4||36B||SH 121 north / FM 2499 north (Grapevine Mills Parkway) / Bass Pro Drive||Westbound exit and eastbound entrance|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- Transportation Planning and Programming Division (n.d.). "Interstate Highway No. 635". Highway Designation Files. Texas Department of Transportation. Retrieved April 2, 2012.
- DeSimone, Tony (October 31, 2002). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways as of October 31, 2002". Route Log and Finder List. Federal Highway Administration. Retrieved September 9, 2007.
- Betz, Jonathan (May 16, 2011). "HOV lanes close on LBJ Freeway as 5-year, $2.7 billion makeover begins in North Dallas". Dallas Morning News. Retrieved May 16, 2011.
- Wheeler, Jason. "After long road, LBJ Express project set to open". WFAA. Retrieved 20 September 2015.
- NTTA. "Trinity Parkway". Retrieved 20 September 2015.