State Highway 45 Southwest

State Highway 45 Southwest is a four-lane, 3.6-mile toll road in Buda, Texas. Connecting two major thoroughfares, the highway provides needed congestion relief, safer local transportation and improves air and water quality by offering an alternative to gridlocked neighborhood streets. 

Constructed around sensitive environmental areas, including the 1,250-square-mile Edwards Aquifer Recharge Zone, McCarthy took extensive environmental protection measures to safeguard these vital areas. The Edwards Aquifer is the key supplier of water in San Antonio and parts of Austin. 

The environmental needs of the project presented unique challenges that required extensive planning and collaboration between all project stakeholders. In partnership with an Independent Environmental Compliance Manager, McCarthy assembled an effective team dedicated to handling all issues as they were identified. As new subcontractors and other personnel joined the project team throughout construction, they underwent environmental training, which mitigated environmental missteps and kept the project on schedule. 

Construction of the highway included Construction Exclusion Zones to protect natural areas and a Prohibited Activity Layout (PAL) was developed, which prohibited staging materials, parking vehicles, fuel storage and other activities in designated areas. In total, more than 60 percent of the project was covered by the PAL and required detailed planning to execute work, sometimes requiring the relocation of materials up to half a mile at the end of the shift to protect the surrounding area. 

The project also features 4.5-mile-long trail local community members can use for walking or biking. The trail includes 14 informative and highly visual signs celebrating the region, and no-mow zones along the path preserve native grasses and wildflowers grown from a custom seed mix designed by Austin’s Lady Bird Johnson Wildflower Center. 

In order to improve ride-quality control, McCarthy used advanced Permeable Friction Course asphalt to greatly reduce bumps in the road. The project received two awards for its use of this paving method: the National Asphalt Pavement Association’s Quality in Construction Award and the Texas Asphalt Paving Association’s Paving Quality Award. 

Other innovations on the project include new wrong-way driving detection technology, the first of its kind in Central Texas. The system actively monitors and detect wrong-way entrants at four locations, deploys countermeasures, and alerts drivers, first responders, and the Traffic & Incident Management Center. The project also features water detention ponds, which allow silt and debris in water that falls onto the road to settle out before being released via timed valves.  

In addition to building in an eco-friendly setting, State Highway 45 is adjacent to a residential neighborhood. In order to minimize disruption to the neighborhood and keep residents safe, McCarthy coordinated with the local Home-Owners Association to notify residents of major changes. Part of the highway was built out of sequence to accommodate safe passage for school buses. The McCarthy team coordinated with the local school district and residents in order to plan around school bus routes.