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Project 2North Central Freeway (US 75) and High

Five Interchange ReconstructionDallas, Texas

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North Central Expressway Constructed 1947 (4-6 lanes) Capacity exceeded after

about 10 years Initial planning for more capacity

Started in early 1970s More lanes in existing ROW Double deck (similar to Austin I-35) Broadly opposed (twice)

Noise Aesthetics Maintenance of traffic concerns ROW acquisition

By 1980, congestion 12 hours/day

NCE near Walnut Hill looking south toward downtown in 1959. Source: http://www.texasfreeway.com/dallas/historic/photos/images/us75_central_walnut_hill_looking_south_2_1959.jpg

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North Central Expressway

Same segment 29 years later (before improvement)

NCE near Walnut Hill looking south toward downtown in 1988. Source: http://www.texasfreeway.com/dallas/historic/photos/images/tti_us75_walnut_hill_may_88.jpg

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Collaborative Approach – Early 1980s North Central Task Force

City of Dallas TxDOT Chamber of Commerce DART Property owners Business leaders Elected officials

Initiated North Central Project (~10 miles) 10 miles Collaborative Consensus plan Meet corridor objectives, concerns Led by C of C Transportation Committee chair Nationally respected project manager Multidisciplinary deign team

North Central Task Force Organization. Source: North Central Task Force reports

Ultimate Proposal 8+ lanes

At-grade and depressed sections

Extensive retaining wall to reduce ROW needs

Cantilevered frontage roads (some)

LRT in tunnel under frontage road

Aesthetics package (renowned architect)

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Typical cross-sections: north, central, south sections

Features – Before and After

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Section of NCE at Northwest Highway interchange showing existing and improved configurations (visualization). Source: Regional Mobility Initiatives, NCTCOG, Vol. 11, No. 1, July 1997.

Features

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Source: http://www.texasfreeway.com/Dallas/photos/us75/us75.shtml

Features

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Source: TTI

Features

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DART LRT line at north end of tunnel under NCE. Source: Regional Mobility Initiatives, NCTCOG, Vol. 11, No. 1, July 1997.

“High Five” Interchange Project

Last part of NCE project Followed NCE north and south of I-635 Delayed due to cost and funding Full replacement

10Before reconstruction. Looking south on US 75 at I-635. Source: TTI

Project Components

Fully directional high speed ramps NCE widened to 8 basic lanes Accommodate wider I-635 Include HOV ramps Maintain existing number of lanes during

construction

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Construction duration Impact of construction on businesses

Issues

CSS Solution

Collaboratively discuss needs and possible solutions Extensive public outreach Reduce construction duration

Innovative construction techniques Contractor flexibility to innovate Incentives/disincentives Night construction Off-site pre-casting

Maintenance of traffic Existing number of lanes during day

Coordinate other improvements with High Five schedule

12Photo: Segment erector technology. Source: http://www.urbantransport-technology.com/projects/dallas_1/dallas_19.html

Expediting Construction

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Erecting bridges by pre-cast sections. Source: http://www.houstonfreeways.com/modern/dfw_high_five_2003-10-27.aspx

Expediting Construction

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Expedited construction while maintaining original number of lanes. Source: Eric Slotboom

Result

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Source: Google Earth

Before reconstruction. Looking south on US 75 at I-635. Source: TTI

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NCE near downtown in 1958. Source: http://www.texasfreeway.com/dallas/historic/photos/images/us75_central_n_of_downtown_july_1958.jpg