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Sam Rayburn Tollway (State Highway 121) Improvements (Section 3N)
Collin County, Texas
  •  The geometry for 12 ramps was constrained by access control determined using outdated AASHTO vertical curve criteria. The estimated construction cost on this project is $70 million.


  • Bridgefarmer developed plans, specifications and estimate for this project which included mainlane electronic toll gantries, four electronic gantrys and a total of 12 bridges in just four months.



Six wrap-around retaining walls (over 166,000 sf) were designed and located based on NTTA system-wide design guideline criteria and their interaction with special drainage needs. Construction plans were designed according to NTTA standards and coordinated with the adjoining section. Redesigned the profile saving $12 million. Accelerated schedule with delivery of final plans four months after NTP instead of the original six months, thereby saving $20 million due to changed market conditions and allowed NTTA an early opening of the corridor.