Wolfensberger Roundabout Design

Challenge

The Town of Castle Rock, Colorado, is ranked as one of the fastest-growing cities in the United States. With this growth came added strain on its roadways, particularly at the intersection of Wolfensberger Road and Plum Creek Parkway. The intersection had previously operated with a four-way stop, which was no longer sufficient to handle the rising traffic volumes or maintain safe operations. As a major connector within the Town’s transportation network, the intersection needed improvements that could keep pace with demand, reduce congestion, and enhance safety for drivers traveling through the community. 

Solution

SEH partnered with the Town of Castle Rock to determine the best solution to solve existing and future traffic conditions as outlined in the community's traffic master plan, with a roundabout chosen as the preferred option. RODEL (a specialized roundabout analysis tool) was utilized to evaluate roadway activity to ensure the appropriate size and configuration for design. From there, SEH designers created a preliminary layout that prioritized smooth traffic flow and safe driver navigation, carefully considering how the roundabout would function as traffic patterns evolve.

The design process required a detailed review of the site itself. The team examined the location to identify potential right-of-way impacts, drainage considerations, and utility conflicts. By addressing these factors early, SEH helped the Town avoid costly delays and ensured the roundabout could be built seamlessly within the existing roadway system. This proactive approach laid the foundation for a design that was both practical and forward-looking.

Once the layout was confirmed, the team developed detailed signing and pavement marking plans for the roundabout and surrounding roadways. These elements were critical to helping drivers navigate the new intersection with confidence, reducing confusion, and ensuring safe operations. The team worked to incorporate proven safety features that are unique to roundabouts, designed to slow traffic speeds and reduce the likelihood of severe collisions compared to traditional intersections.

Because Wolfensberger Road and Plum Creek Parkway serve as vital connectors within Castle Rock, it was equally essential to maintain traffic flow throughout construction. The team designed a comprehensive construction phasing and traffic control plan that kept vehicles moving while work was underway. This careful coordination limited disruptions to nearby residents and businesses and ensured commuters could continue to rely on the intersection during the project.

By the end of construction, the Town had replaced an outdated four-way stop with a modern roundabout that supports current traffic demands while planning ahead for future growth. The project was completed on schedule and closely coordinated with nearby roadway improvements along Meadows Parkway, creating a more cohesive transportation network.