Halff’s RM 620 Railroad Overpass and Roundabout Project Earns ACEC Honor Award

WASHINGTON, D.C. — Halff has been recognized with its first ever honor award from the American Council of Engineering Companies (ACEC) for the RM 620 Railroad Overpass and Roundabout project. Presented at the ACEC Engineering Excellence Awards gala, the recognition places the project in the top 12% of entries nationwide, celebrating outstanding achievement in engineering design and innovation.

A joint effort by the City of Round Rock, Williamson County, the Texas Department of Transportation (TxDOT) and consultant, Halff delivered an innovative engineering design for the RM 620 Railroad Overpass and Roundabout, resolving decades of traffic congestion and enhancing safety between Deep Wood Drive and IH-35 in Round Rock.

As the prime engineering consultant for this project, Halff provided schematic design, environmental and final design, including plans, specifications and estimates for the roadway, drainage, water quality facilities, water and wastewater, landscaping, hardscaping and aesthetics. Halff also provided subsurface utility engineering and utility coordination.

The RM 620 Railroad Overpass and Roundabout was recently honored with an ACEC Honor Award at the ACEC Engineering Excellence Awards Gala in Washington, D.C.

RM 620 had endured decades of traffic congestion caused by an at-grade railroad crossing and limited alternative routes. Slow-moving rock trains traveling from a nearby quarry would block traffic on RM 620, backing it up into an adjacent intersection with IH-35. The roadway serves commuters, area businesses, a residential neighborhood, places of worship, Round Rock High School and nearby Round Rock Medical Center, handling as much as 40,000 Average Annual Daily Traffic (AADT). An overpass and road widening were needed, but the area had fully developed with homes and businesses lining both sides of the corridor, so expanding to a full freeway section would have been highly disruptive and displaced dozens of businesses.

The Halff design team endeavored to right-size the project, balancing the need for additional traffic capacity and a bridge overpass with the desire to limit the environmental footprint and the number of homes and businesses displaced by the project. By soliciting input from a large swath of community stakeholders and agencies, the design process emphasized safety, functionality, minimization of property and environmental impacts, and incorporated locally inspired aesthetic features. The optimized design saved more than $12 million compared to previous schematic designs.

When posed with a challenging six-legged intersection at Chisholm Trail Road and two at-grade railroad crossings, the design team developed a unique and innovative solution by designing an at-grade roundabout intersection with the railroad tracks crossing through the middle and a bridge handling 90% of the traffic to span all of it. The design team worked with the city to realign the roadway to the south to minimize traffic disruption during construction and repurpose the two existing rail crossings to serve as the eastbound and westbound crossings of the roundabout.

Roadway grade separations over railroad tracks are common, and roundabouts are becoming more common, but the combination of a grade separation over a roundabout bisected by the at-grade railroad crossing was a creative and much safer engineering solution to what had long been an impediment in the community.

RM 620 received an ACEC Texas Gold Medal in the transportation category last year. In total, Halff has won five ACEC National Awards: Bastrop State Park Dam (2024), the East Austin Emergency Utility Repair (2023), FAMU Way (2022) and the City of Fort Worth Storm Drain Rehabilitation Program (2022). Earlier this year, Halff’s Bastrop State Park dam was also recognized with an APWA National Project of the Year Award in the Historical Restoration/Preservation category for projects between $5 million and $25 million.

About the Firm

Halff is an award-winning, employee-owned and full-service infrastructure consulting firm celebrating a legacy of 75 years of improving lives and communities. Founded in 1950 by Dr. Albert H. Halff, the firm has built a legacy of delivering innovative solutions with a people-focused approach.

Operating from more than 30 offices across Arkansas, Arizona, Florida, Louisiana, Oklahoma and Texas, Halff is a leader in design excellence and community impact, earning more than 80 project awards since 2021. For four consecutive years, Halff has ranked as an Engineering News-Record Top 100 Design Firm and as a USA TODAY National Top Workplace.