Infrastructure Design Within Natural Spaces

Nature-filled hiking trails and breathtaking vistas lie within wildlife refuges, along remote access roads, and near federal and tribal lands across the country. While visitors look to enjoy these calm, serene places, many end up finding full parking lots, experiencing hours of traffic delays and crowded trails.

We all love our natural surroundings, but are we loving them to death? How do you preserve the natural landscape for future generations, provide an excellent visitor experience and enable safe and reliable access to remote areas and roadways?

Many factors go into planning and designing around nature to ensure adequate infrastructure is sensitive to the landscape. The influx of funding from the Bipartisan Infrastructure Law (BIL) and the Great American Outdoors Act (GAOA) has made delivering these projects even more complex, adding to the urgency to prioritize.

There’s not a one-size-fits-all approach. Each project is unique, specifically when working within public lands. Many projects include accessibility, cultural preservation, sensitive landscapes, endangered species, resiliency, and other management challenges such as safety, congestion management, and visitor experiences.

Collaborating with project stakeholders is crucial to understanding the vision and goals early on so that creative solutions can be developed that factor into these important considerations.  A great example of this was on a recent project at Yosemite National Park.

The roadways within Yosemite Valley were designed in 1927 when the park had fewer than 500,000 visitors annually. In recent years, visitation has increased to nearly 5 million, creating significant congestion and safety concerns. Yosemite National Park needed solutions to eliminate congestion and improve the experience for all visitors, whether traveling by car, on foot, on a bike or using the park shuttle system.

Our experts creatively applied analysis tools and models to demonstrate the key issues of the circulation system and demonstrate the benefits of proposed solutions. At first glance one might think the easy solution would be to just widen the road to help provide more capacity in critical areas. However, our job as stewards of our national parks is to understand the impacts this would have. Instead, we found creative ways to remove decision-making from visitors and more clearly direct them to their desired locations.

We identified critical bottlenecks which impacted traffic operations in Yosemite Valley on peak visitation days and developed a suite of potential improvements that were vetted with project partners to determine the best solutions. Our team created a custom travel model based on visitor behavior and travel patterns, established baseline conditions and calibrated the model to counts, developed scenarios using feasible network and transit solutions, and analyzed scenarios to determine improvements for implementation.

Our improvements include providing additional capacity without road widening by removing two-way travel and converting to a one-way configuration. The team identified continuous flow intersection solutions to reduce the number of decisions a driver needs to make, thereby simplifying intersections and reducing congestion due to excessive queuing and enhances pedestrian and bicycle connectivity and safety.  The team also got creative and introduced a less typical contraflow circulation pattern where vehicles drive on the “wrong” side of the road to simplify intersections and eliminate congestion. The contraflow configuration of Sentinel Drive allows for mostly uninterrupted traffic flow at the adjacent intersections, thus eliminating the bottleneck. It also enables park staff to manage the number of vehicles accessing some of the most-visited portions of the park where parking becomes unavailable on peak visitation days by redirecting them to other areas of the park with capacity.

While the project did deliver solutions to improve mobility, so many more benefits were realized. Eliminating the congestion improves air quality and helps protect the environment and eases the load placed on park rangers to spend countless hours managing traffic.

The biggest outcome of the project was restoring the amazing vistas and creating more space to enjoy the views of Half Dome and Yosemite Fall.