LBJ highway in Dallas, Texas
Construction, maintenance and management of a 27 km section of the Lyndon B. Johnson (LBJ) Expressway.
The Project was delivered in December 2015, after five years of construction, with zero infractions, fines or environmental penalties.
- 2.7 Billion € investment
- 27 km length
Since it was built 40 years ago, the LBJ highway has become one of the most congested roads in the United States.
The extension project began towards the end of 2010 and was opened in April 2015, on budget and 3 months ahead of schedule, after five years of construction works with zero contingencies, fines or environmental penalties, while remaining open for some 250,000 drivers every day. Its growth projections are for up to 400,000 vehicles driving on the roads every day by the year 2020.
The new LBJ Express doubles the driving capacity of the old LBJ. Up to six new toll lanes have been added in the I-635 section, and four on the I-35 section. This extension aims to cover the needs arising through population growth over the next 30 years.
The most important reconstruction section of the I-635 within this project is the provision of two main interchanges (the I-35E and the North Dallas Tollway), 12 major overhead passes, six overhead passes for slip roads and a walkway for pedestrians (the Joe Ratliff Walkway).
Overall, works have comprised the building of a concrete structure the size of 120 football fields and a wearing surface equivalent to 280 fields, with the excavation of close to 7 million cubic metres of earth. Some 100 km of pilings have been used, 330 km of prefabricated beams and 320,000 m2 of different types of walls have been put up. The 9 lanes in each direction making up the highway have involved the construction of over 350 km of lanes, with one section of the highway having up to 28 lanes.
Innovative funding in the US
This project is the largest PPP (Private Public Partnership) to be developed in the US to date, in terms of complexity and total contract cost.
This new infrastructure allows drivers to opt for using the free lanes for shorter trips, while ensuring shorter driving times on the toll sections.
The LBJ Express is fitted with a managed lanes toll system (or express toll lanes). Drivers can view rate adjustments depending on the average speed or number of vehicles using the express lanes.
Thus, outside rush hours, rates drop compared to times when traffic is heavier. This dynamic pricing system provides a traffic management tool which guarantees drivers that they can carry out their daily commutes more quickly. Drivers can thus opt to pay toll and use the managed lanes, or drive on the renovated free lanes.
Description of the technical project
Works were divided into the following sections:
- I-35E section (from Loop12/IH35E to Crown Rd): This stretch of the project consists of two elevated connectors with two lanes in each direction along the I-35E connecting to the new sections linking it with I-635, as well as the reconstruction and extension of certain sections of the service lanes.
- I-635/I-35E interchange: The current interchange consists of eight direct sections linking the I-35 to the I-635. Four additional slip roads with two lanes in each direction have been added to increase connectivity with the new toll lanes.
- I-635 Section (east of I-35E to US 75 approximately): This section has been fully rebuilt to provide it with free general lanes with at least four lanes in each direction and a maximum of six lanes in specific areas, and two toll depressed sections with three lanes in each direction.
In addition, the current service roads have been improved, increasing existing capacity and extending them to provide continuous service lanes of two to three lanes with access slipways both onto the free lanes and the toll lanes. The length of this section is 14 km.
- I-635/US-75 link: The lanes and slipways in this section have been redesigned to modify the HOV lanes on I-635 between US-75 and Greenville Avenue and thus fully connect toll lanes and free lanes.
Thanks to a stringent accident prevention programme covering 9,000 workers, the LBJ Express project was completed with a safety incident rate of 1.2, a figure which is well below the national average of 4.2, with no fatalities or serious injuries in the work area after over 16 million hours worked.
Works were carried out under an ISO 9001 quality system and an ISO 14001 environmental control system, with the LBJ being the first construction project in the state of Texas to comply with this essentially European standard.
The Environmental Team of the LBJ Express was highly efficient in the application of both creativity and innovation leading to the general success of the project. The LBJ Express project has been – and continues to be –recognised as a model to be followed given the environmental practices used on it.