Publications

Case Study

TOWER FALLS TO TOWER CANYON
YELLOWSTONE NATIONAL PARK

The Federal Lands Highway (FLH), in partnership with the National Park Service, initiated reconstruction of a 2.5-mile stretch of road between Tower Junction and Tower Falls in the northeast section of Yellowstone National Park. The project also included reconstruction of the Canyon Village parking lot and replacement of the Obsidian Creek Bridge at the Indian Creek Campground. The road has tight curves, steep hillsides, and natural walls that make construction challenging. The project exhibited sustainable construction practices, including the following:

• To preserve the historic context of the pre-existing guardrail while adding new stone, masons matched the old with the new material.
• Soils from hillside cuts were trucked elsewhere in the project area to recycle and maintain local materials within the project. The Tower parking lot was expanded using recycled soils. Similarly, large boulders extracted during excavation were placed along walkways or crushed for placement as walls.
• To ensure preservation of nutrient-rich topsoil, it was stockpiled at the construction limit edge; this topsoil was then placed back on the hillside after excavation to ensure preservation of native plant species.
• Roadside trees that were cut down were laid back on the slope to help slow erosion, maintain natural biomass, create habitat, while also avoiding the need to haul materials from the site.

Topsoil is pushed to the top of slope for placement following construction.

Vertical walls make construction challenging through this area.

Large boulders are excavated and placed elsewhere in the project area.

View from the corridor to the valley below

Case Study

MADISON TO NORRIS
YELLOWSTONE NATIONAL PARK

The Madison to Norris project is located on the western section of the Grand Loop in Yellowstone National Park. This 10-mile project addressed multiple deficiencies in pavement, drainage, alignment, and safety using sustainable construction methods and new features that enhanced the visitor experience. The road was widened to 30 feet. Two miles of new alignment were created upstream of Gibbon Falls, mitigating an impacted area and restoring it to natural conditions - prime riparian habitat. Specific sustainable features included:

• A 2-mile realignment of the roadway restored natural environmental conditions, while a new bridge over the Gibbon River was designed to maintain historic character of the area.
• Retaining walls were built with materials from the existing roadway when possible to create natural looking walls and cut slopes.
• The Gibbon Falls area previously had only a small pullout and minimal parking. The viewing and parking areas were expanded and enhanced with bicycle racks and ADA-compliant ramps and walkways.
• Small rocks were placed along roadside ditches to filter, slow, and percolate run-off.

Little evidence exists of the former roadway alignment along the Gibbon River.

New alignment with retaining walls of native stone and bridge over the Gibbon River.

An expanded parking area and pedestrian pathways provide access to the falls viewing area.

Case Study

TETON PATHWAYS
GRAND TETON NATIONAL PARK

The FLH partnered with Grand Teton National Park to plan and construct a 10-foot wide multi-use pathway for cyclists and pedestrians, connecting Jackson Hole, Wyoming, to Grand Teton National Park. The pathway becomes a visitor experience of its own while augmenting the opportunities and modes that visitors use to experience the park. Elements of sustainability are woven into the construction, the visitor experience, and the maintenance of the pathways.

The route connects the County pathway from Jackson Hole to Moose Junction along approximately 8 miles of a separated pathway through the sagebrush flats east of the Teton Range. Path users can view grazing bison
and elk. Interpretive signage helps orient and educate path users who will be traveling at a pace ideal for continual interaction with the landscape. The pathways feed into the visitor circulation systems within the busiest part of the park while signals, signage, and integrated pathway design emphasizes safety for vehicle and non-vehicle users.

Sustainability is integrated into the experience. Instead of visiting the park via automobile, the pathway encourages visitors to experience the park by other modes, lessening the environmental impact caused by vehicles and expanding recreational opportunities.

Experiencing the park at a slower pace allows visitors to see more of the environment without potentially harming wildlife. Highlighting wildlife crossings, natural, and historic locations with signage educates visitors - an important step toward cultivating a sense of environmental ethic and responsibility.

bicycle racks

Trail crossing

Pathway

Case Study

GOING-TO-THE-SUN ROAD
GLACIER NATIONAL PARK

The "Sun Road" is a 50-mile two-lane highway that winds through Glacier National Park, up the slopes of the Continental Divide, and over Logan Pass. Mostly built between 1921 and 1937, the road is considered an engineering feat and National Historic Landmark. The roadway and roadside embody sustainable design practices from a number of perspectives:

• New avalanche-resistant guard walls have been constructed with a reinforced concrete foundation and core, then finished with stonemasonry facing to maintain consistency with the historic character.
• Removable guardrails have been installed to allow avalanches to pass over the roadway without roadway/wall damage. The guardrails are both historically authentic and aesthetically pleasing.
• To ensure safety and remove rockfall hazards, rock scaling has been conducted to remove loose and unstable slabs. To help support unstable rock, holes are drilled below the rocks that are to be stabilized, steel dowels are inserted, shotcrete is applied and then shaped, textured, and colored to blend with the surroundings.

Installation of guard walls with reinforced concrete;

Roadway construction;

Removable guardrail installation

Source: "Preserving a Landmark in the Sky: Rehabilitation of the Going-to-the-Sun Road" (2008).

Case Study

KATHERINE ACCESS ROAD
LAKE MEAD NATIONAL RECREATION AREA, ARIZONA

This project involved a combination of widening and overlaying the existing road bed to alleviate unsafe and inadequate lane widths along a 3.8-mile stretch of Katherine Access Road. Safety enhancements included asphalt curbing and guardrail replacements, updating existing culverts, and evaluating and improving the design of the boat launch and parking area to alleviate drainage problems and facilitate safer traffic movements. Initial safety issues documented along the roadway included:

• Culverts in the roadway clear zone
• Steep slopes adjoining the roadway with no associated barriers
• Absence of roadside shoulders
• Steep grading cuts undermining the roadway

To mitigate these roadside safety concerns, the project team instituted sustainable practices:

• Re-aligning and lengthening culverts to remove entrances from clear zones
• Installing contextually designed guardrails along sections of roadway that border steep slopes
• Adjusting roadway curvature to eliminate steep cuts in an effort to minimize erosion and provide for a safe shoulder area
• Re-grading steep side slopes to reduce erosion, encourage re-vegetation, and protect motorists

Steep roadside embankments without shoulder

The images show the pre-existing condition as project construction has not yet begun.

Culvert entrances located within clear zone, creating a hazard for motorists.

Steep side slopes without guardrails.