High Five Interchange
Encyclopedia
The High Five Interchange is a five-level freeway interchange
, designed by the HNTB Corporation, that connects Lyndon B. Johnson (LBJ) Freeway (Interstate 635
) and Central Expressway
(US 75) in Dallas
, Texas
, United States
. The High Five is the first five-level stack interchange
in Dallas.
The $261 million project began in 2002 and was completed in December 2005.
As part of the project, I-635 was widened to include high-occupancy vehicle lanes
("HOV lanes"). The new lanes for regular traffic were built on the outer vacant right-of-way, while the HOV lanes were built in the median. The original I-635 lanes passing through the former interchange, now demolished, lay between the new regular and HOV lanes.
During construction staging, to maintain traffic flow, most of the flyover ramps were built over the existing parclo interchange. The old junction could then be demolished with little disruption once the new lanes were operational. Virtually none of the original junction remains after the reconstruction.
The interchange comprises 37 bridges distributed across 5 levels (thus the name "High Five"), with the highest ramps 120 feet (37 m) above ground. The High Five consists of a total of 710 support tiers, 30,000 feet of drainage pipes and nearly 60 lane-miles of new roadway and stretches 2.4 miles (3.9 km) north/south and 3.4 miles (5.5 km) east/west.
From top to bottom, the highways on the five levels are:
The High Five also incorporated a hike and bike trail, named the Cottonwood Trail, which runs under all levels of the interchange. The section of the trail passing beneath the interchange was constructed as part of the High Five project by the Texas Department of Transportation.
named the High Five "a Public Works Project of the Year".
Interchange (road)
In the field of road transport, an interchange is a road junction that typically uses grade separation, and one or more ramps, to permit traffic on at least one highway to pass through the junction without directly crossing any other traffic stream. It differs from a standard intersection, at which...
, designed by the HNTB Corporation, that connects Lyndon B. Johnson (LBJ) Freeway (Interstate 635
Interstate 635 (Texas)
Interstate 635 or the Lyndon B. Johnson Freeway is a partial loop around Dallas, Texas between Interstate 20 in Balch Springs, Texas and State Highway 121 at the north entrance of the Dallas-Fort Worth International Airport in Grapevine, Texas. The route is long...
) and Central Expressway
Central Expressway (Dallas)
Central Expressway is a north–south highway in Dallas, Texas and surrounding areas.- North Central Expressway :The best-known section is the North Central Expressway, a name for a freeway section of U.S. Highway 75 between downtown Dallas and McKinney, Texas...
(US 75) in Dallas
Dallas, Texas
Dallas is the third-largest city in Texas and the ninth-largest in the United States. The Dallas-Fort Worth Metroplex is the largest metropolitan area in the South and fourth-largest metropolitan area in the United States...
, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. The High Five is the first five-level stack interchange
Stack interchange
A stack interchange is a free-flowing grade separated junction between two roads.In countries where one drives on the right, left turns are handled by semi-directional flyover/under ramps...
in Dallas.
The $261 million project began in 2002 and was completed in December 2005.
Scope
The former interchange was a partial cloverleaf interchange ("parclo") modified for freeway speeds. The westbound lanes of I-635 were two levels above the eastbound lanes, while the intersecting US 75 was the mid-level of the interchange, crossing eastbound I-635 and then passing under westbound I-635.As part of the project, I-635 was widened to include high-occupancy vehicle lanes
High-occupancy vehicle lane
In transportation engineering and transportation planning, a high-occupancy vehicle lane is a lane reserved for vehicles with a driver and one or more passengers...
("HOV lanes"). The new lanes for regular traffic were built on the outer vacant right-of-way, while the HOV lanes were built in the median. The original I-635 lanes passing through the former interchange, now demolished, lay between the new regular and HOV lanes.
During construction staging, to maintain traffic flow, most of the flyover ramps were built over the existing parclo interchange. The old junction could then be demolished with little disruption once the new lanes were operational. Virtually none of the original junction remains after the reconstruction.
The interchange comprises 37 bridges distributed across 5 levels (thus the name "High Five"), with the highest ramps 120 feet (37 m) above ground. The High Five consists of a total of 710 support tiers, 30,000 feet of drainage pipes and nearly 60 lane-miles of new roadway and stretches 2.4 miles (3.9 km) north/south and 3.4 miles (5.5 km) east/west.
From top to bottom, the highways on the five levels are:
- I-635 exit ramps to US 75 and direct HOV connector, reversible for either EB I-635 to NB US 75 or SB US 75 to WB I-635
- US 75 exit ramps to I-635
- I-635 (LBJ Freeway)
- Frontage roads for US 75 and I-635
- US 75 (North Central Expressway)
The High Five also incorporated a hike and bike trail, named the Cottonwood Trail, which runs under all levels of the interchange. The section of the trail passing beneath the interchange was constructed as part of the High Five project by the Texas Department of Transportation.
Awards
In 2006, the American Public Works AssociationAmerican Public Works Association
The American Public Works Association is a not-for-profit, professional association of public works agencies, private companies, and individuals dedicated to promoting professional excellence and public awareness through education, advocacy and the exchange of knowledge...
named the High Five "a Public Works Project of the Year".
