FHWA-WFL/TD-08-001 January 2008

Federal Highway Administration

U.S. Department of Transportation

National Park Service

U.S. Department of the Interior

January 2008

National Park Service

U.S. Department of the Interior

Welcome to Glacier National Park

Beginningin the late1800s, visitors startedarriving at what is now knownas Glacier

National Park. In 1900 the area was recognizedas a ForestPreserve but was still open

to miningand homesteading. President Taft in 1910designated the landas a National 

Park,thetenthin the nation.

Theconstruction oftheGoing-to-the-Sun Roadwasa huge undertaking. Even today, 

visitors tothepark marvelat how sucharoad could have been built. The finalsection 

of the Going-to-the-SunRoad,over Logan Pass, was completed in 1932 after 11 

years of work. The roadis consideredan engineering featand is a National Historic

Landmark. It is oneof the most scenic roads inNorth America. The constructionof

the road forever changed the way visitorswouldexperience Glacier National Park. 

Future visitors would drive over sectionsof the park that previously hadtaken days

of horseback riding to see. 

Just acrossthe border, in Canada, isWaterton Lakes National Park. In 1931, members

of the Rotary Clubsof Alberta and Montana suggested joining the two parks asa

symbol of the peace and friendship between our two countries. In 1932, the United 

States and Canadian governmentsvoted to designate the parks as Waterton-Glacier

International PeacePark, theworld’s first. More recently the parks havereceived

twootherinternational honors.The parks areboth Biosphere Reserves, and were

namedas a World Heritage Site in 1995.This international recognition highlights the 

importance ofthis area, not just to the United States and Canada, but to theentire

world.

Whilemuch has changed since the fi rst visitorscame toGlacier, itis possible to relive

some ofGlacier’s earlyhistory. You can take ahorsebackride like an early visitor.

Milesof hikingtrails followroutes fi rst usedby trappersin the early 1800s. Several

hotels and chalets, built by the Great Northern Railwayin the early 1900s, house

summer guests. A visit toGlacierNational Parkis still a great adventure!

Come and experience Glacier’s pristine forests, alpine meadows, rugged mountains,

andspectacular lakes. With over 700 miles of trails, Glacieris a hiker’s paradise for 

adventurous visitors seeking wilderness and solitude. Relive the daysof old through

historic chalets, lodges, transportation, andstoriesof NativeAmericans. Explore

Glacier National Parkand discover whatawaits you.

Report Number: FHWA-WFL/TD-08-001
The Going-to-the-Sun Road in Montana’s Glacier 

National Park was once described as “the most 

beautiful piece of mountain road in the world.” 

Those words, spoken by park Superintendent Eivind 

Scoyen to several thousand spectators at the road’s 

1933 dedication ceremony, will continue to ring true 

for many users now that a historic rehabilitation is 

underway.

The Sun Road, as some abbreviate it, is an 80.5-

kilometer (50-mile), two-lane highway that winds 

through the heart of the park, up the steep slopes of 

the Continental Divide, and over 2,026-meter (6,646-

foot) Logan Pass. Motorists can experience what 

some view as the most spectacular mountain scenery 

in North America -- glacier-carved peaks, deep blue 

lakes, and lush forests.

The highway itself, built mostly between 1921 and 

1937, is considered an engineering marvel by virtue 

of its designation as a National Civil Engineering 

Landmark. Most of the 19-kilometer (12-mile) “alpine,” 

or high mountain, section over Logan Pass was built 

into the sides of near-vertical cliff s using a network of 

stonemasonry bridges, tunnels, and arches. A series 

of 130 retaining walls support the roadbed along 

the steepest sections, and more than 11 kilometers 

(7 miles) of guard walls and guardrails help guide 

motorists and keep them on the road. These 

stonemasonry guard walls give the road much of its 

historic character and architectural aesthetic appeal. 

Amy Vanderbilt 

& 

Steve Moler

Federal Highway 

Administration 

and the National 

Park Service 

embark on a 

monumental 

restoration of 

Montana’s historic 

Going-to-the-Sun 

Road

Most of the guard walls along the Going-to-the-Sun Road near Triple Arches were either sheared off or damaged by avalanches 

and rockslides. Some of the old guardrails are visible in the foreground. As part of the restoration of the road, a new generation of 

removable steel-backed guardrails, seen in the background, are installed prior to the spring road opening and removed when the 

road closes in the fall so avalanches can travel over the road without causing damage.

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Today the Sun Road has more than 

475,000 vehicles traveling it during 

Glacier’s peak visitor season from June 

to October, or about 3,500 vehicles per 

day. Approximately 80 percent of the 

park’s two million annual visitors travel 

the road, according to park surveys.

However, 70 years of rockslides 

and avalanches, severe weather, heavy 

traffi c, and inadequate maintenance 

left the road in urgent need of repair. 

Without aggressive action, the historic 

structures for which the Sun Road is so 

admired might have been lost forever.

PRESERVING A NATIONAL TREASURE

The National Park Service (NPS) and Federal 

Highway Administration (FHWA) have embarked 

on a monumental rehabilitation project to save this 

national treasure. Indeed, the most urgent repairs 

on structures in danger of catastrophic failure were 

completed during previous phases. The two agencies 

originally intended to invest $140 million to $170 

million over 7 to 8 years to restore the Sun Road’s entire 

length. However, due to a lack of available funding, 

complete rehabilitation could take longer. According 

to the latest estimates, the rehabilitation is projected 

to last up to 10 years at a cost of $250 million. Both 

agencies, in partnership with local, State, and Federal 

offi cials are committed to completing the Sun Road 

rehabilitation in the soonest possible timetable 

as funding allows. The eff ort involves repairing 

damaged and deteriorating stonemasonry retaining 

walls and guard walls, inadequate drainage systems, 

crumbling pavement, and tunnels and bridges. Safety 

improvements will be made at high-priority rockfall 

locations and at pullouts, overlooks, and parking 

areas. A comprehensive mitigation program will limit 

impacts on tourism.

“This is the largest and most complex project 

our offi ce has ever undertaken,” says Ricardo Suarez, 

project delivery director and acting division engineer 

for FHWA’s Western Federal Lands Highway Division 

(WFLHD), which is jointly managing the project with 

NPS.

The project is also one of the largest road 

rehabilitations in NPS history, according to Glacier 

Superintendent Mick Holm. “The road is not the only 

jewel in the park’s ‘crown,’ but a trip across the Sun 

Road does provide an iconic experience for a vast 

number of Glacier’s visitors,” he says. “The scope and 

magnitude of this project is clearly unprecedented 

and daunting. But I believe we can and must do 

nothing short of completing this rehabilitation in a 

timely manner, thereby preserving this phenomenal 

mountain byway experience for generations to 

come.”

A MONUMENTAL TASK

The Sun Road rehabilitation actually began in 

the late 1980s at the village and park entry point of 

West Glacier. The remaining work involves about 13 

construction phases in all. The fi rst four, to rehabilitate 

the most severely damaged retaining walls, have 

already been completed through Park Roads and 

Parkways funding, a joint NPS-FHWA program to 

develop and maintain roadways throughout the 

national park system. Phase 5 was completed in 2005 

and involved rehabilitating the West Side Tunnel’s 

east portal and high-priority guard walls, correcting 

various drainage and roadside defi ciencies, and 

repairing damage from a recent rockslide.

But it is the remaining phases that have turned the 

Sun Road work into an extraordinary project. Those 

phases involve rehabilitating the entire roadway 

itself and making the most critical and complex 

From east to west, the Going-to-the-Sun 

Road, shown here in red, starts in the village 

of Saint Mary, follows the northern shore of 

Saint Mary Lake, passes Going-to-the-Sun 

Mountain, climbs to Logan Pass, hugs the 

Garden Wall and turns the Loop, then follows 

McDonald Creek down to the southern shore 

of Lake McDonald, ending in the village of 

West Glacier.

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A ROAD–AND HISTORY–IN THE MAKING

The fi rst tourists to visit what is now Glacier National Park came by 

train beginning in the 1890s. A typical trip involved getting off the train at 

the Great Northern Railway’s Belton Station in present-day West Glacier, 

taking a 4.8-kilometer (3-mile) stagecoach ride to Lake McDonald, and 

then traveling by boat to the Lewis Glacier Hotel, now Lake McDonald 

Lodge. Guests also could go by horseback to backcountry lodges and 

chalets.

The automobile’s proliferation at the start of the 20th century 

drastically changed the travel scenarios. By the time Congress designated 

Glacier a national park in 1910, many 

visitors already were arriving by private 

automobile via old wagon trails and 

dirt roads. Demand soon increased for 

a better road system that would allow 

enjoyment of the spectacular scenery 

without damaging the environment.

The concept was bolstered when 

Congress provided $100,000 annually in the early 1920s for construction of the 

“Transmountain Highway,” as the Sun Road was fi rst named. This was enough to start 

work on the road’s fl atter east and west ends in 1921. Construction of the more rugged 

central section over the Continental Divide loomed as a far greater challenge.

In 1918 NPS engineer and acting park superintendent George Goodwin had 

proposed a route similar to today’s alignment, except that it included a steep climb 

over Logan Pass via 15 switchbacks and hairpin turns. Goodwin’s proposal was typical 

of engineering at the time: It was fairly scenic, followed the shortest possible route, and 

above all was economical.

But NPS policy had come to stress the importance of “harmonizing park 

improvements with the landscape,” and concerns about the plan were expressed 

during a route inspection in the summer of 1924. NPS Director Stephen Mather asked 

Thomas Vint, an agency landscape engineer, to review Goodwin’s proposal. Vint said 

the switchbacks would look “like miners had been in there.” Instead he proposed a road 

carved directly into the Garden Wall, a 4.8-kilometer (3-mile) section of nearly vertical 

cliff s near the summit of Logan Pass.

Vint’s route was eventually chosen because it provided fl atter grades, less 

environmental impact, better panoramic views, more sun exposure for faster spring 

snowmelt, and only one switchback—The Loop. The project received its second large 

cash infusion when Congress appropriated $1 million in 1924 and 1925 specifi cally for 

the Transmountain Highway.

In January 1926, NPS and the Bureau of Public Roads (BPR)—the predecessor agency to FHWA—signed a memorandum 

of agreement outlining how they would cooperate in building the road. The agreement combined BPR’s high engineering 

standards and expertise with NPS’s vision for preserving the landscape. It became the model for future national park road 

building and the basis for today’s Park Roads and Parkways program, still a joint NPS-FHWA eff ort.

BPR soon accepted bids for construction of the western 19.3-kilometer (12-mile) stretch from Logan Creek up to 

Logan Pass, the most challenging section of the road and including Vint’s route and single switchback. The construction 

fi rm (Williams and Douglas-Tacoma, WA) worked on the section 

for four seasons, building retaining walls, guard walls, Logan Creek 

Bridge, the West Side Tunnel, and Haystack Creek Culvert and Triple 

Arches.

Two other companies constructed the remaining 16 kilometers 

(10 miles) on the east side of Logan Pass in 1931 and 1932. The most 

diffi cult challenge was constructing the 123.5-meter (405-foot) East 

Side Tunnel. Workers had to carry out all the excavated rock by hand 

because power equipment could not reach the tunnel. One section 

was so remote that a power shovel had to be barged up St. Mary 

Lake to reach it.

In October 1932, after more than three decades and $2 million 

of construction, the fi rst automobile drove the entire 80.5 kilometers 

(50 miles) of the new road, which was offi cially opened in a dedication 

ceremony on July 15, 1933. The road then was renamed after the 

nearby Going-to-the-Sun Mountain, which many think is the most 

aptly named road in the Nation given that motorists feel like they are 

traveling toward the sun as they ascend it.

Workers drag drainage pipes by horseback in 1927 

during construction of the road west of Logan Pass.

A historic red bus in the late 1920s 

rounds The Loop, the only switchback 

constructed on the Going-to-theSun Road. The entire fl eet of original 

red “jammers” (so called by the locals 

because the drivers could be heard 

jamming the gears on the rugged 

mountain road) still operates in the 

park today.

A crew uses a power shovel east of Logan Pass in 1932. 

Going-to-the-Sun Mountain, for which the road is named, 

is seen in the background.

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7

repairs to historic structures along the alpine section. 

Under a more typical schedule, this work would have 

been completed in small segments over a much 

longer period, but for economic and environmental 

reasons, NPS and WFLHD have decided to accelerate 

construction so the fi nal phases can be completed 

more rapidly than past repairs.

The fi nal phases were assessed under an 

environmental impact statement (EIS) and two 

records of decision (RODs), one by the NPS and the 

other by WFLHD. All the work will be done while the 

road remains open during the normal tourist season. 

The RODs were based on an accelerated rehabilitation 

schedule and were dependent on projections of 

increased project funding from the Park Roads and 

Parkways program; a congressional earmark from 

the new transportation reauthorization bill, the Safe, 

Accountable, Flexible, Effi cient Transportation Equity 

Act: A Legacy for Users; and other sources.

“I compare the Sun Road rehab to the restoration 

of the Statue of Liberty in the mid-1980s,” says 

Ron Carmichael, former WFLHD division engineer 

who worked on the project during most of its early 

planning until retiring in September 2005. “Like the 

statue, the Sun Road is a national treasure that has 

fallen into disrepair. It is our obligation to rehab the 

road in a way that replicates the intent of the original 

constructors while preserving the historic and 

cultural resources and the visitor experience that was 

originally intended.”

MANY CHALLENGES AHEAD

Construction on the remaining phases is 

expected to be complex and challenging, according 

to engineering studies. Work can be done only 5 

to 6 months of the year, typically mid-May to midOctober, because of harsh weather and the annual 

winter road closure. The terrain where much of the 

work will be performed is steep, and the roadway is 

extremely narrow, less than 6 meters (20 feet) wide 

along many stretches. Adding to the diffi culties is the 

requirement that the road remain open throughout 

the entire rehabilitation. Finally, its designation as a 

National Historic Landmark requires NPS and WFLHD 

to minimize harm to the road’s historic character and 

fabric in accordance with the Secretary of Interior’s 

Standards for the Treatment of Historic Properties and 

related Federal and State regulations.

Many retaining walls, like this one near Crystal Point, are 

being “repointed,” the process of removing and replacing 

damaged and deteriorated mortar. Here a crane lowers 

a worker, enclosed for safety in a cage-like basket, to 

perform repairs.

FHWA Resident Engineer Margaret Moen, who worked on the 

project until early 2006, inspects a construction site where a new 

and hidden concrete retaining wall was constructed inside the 

original wall, allowing the historic wall to maintain its original 

appearance without having to support its former structural 

load.
8

Rehabilitation will focus on fi ve high-priority 

engineering areas:

Retaining walls, arches, and tunnels. Many of 

the road’s stonemasonry retaining walls suff er from 

structural deterioration, primarily from age and 

impacts from rockslides, vehicles, and avalanches. 

Damage also has been caused by rain and snowmelt 

repeatedly freezing and thawing inside and behind the 

walls. Thirteen retaining walls, determined by WFLHD 

to be in immediate danger of catastrophic failure, were 

repaired in the fi rst four phases. Remaining problems 

include decaying and inadequate foundations, poor 

embankment stability, inadequate drainage, and the 

breakdown of mortar (the binding that holds the 

stones together).

To solve these problems, many sections of 

retaining walls either have been or will be “repointed” 

with new mortar. In more severe cases entire walls will 

be rebuilt. Some retaining walls will be preserved by 

building second, hidden walls behind them to carry 

some of the structural load.

Guard walls and removable guardrails. Many 

sections of the road’s stonemasonry guard walls have 

suff ered damage from age, impacts from vehicles, 

avalanches, and rockslides, and improper repairs over 

several decades. As with the retaining walls, water 

seepage has caused cement on some guard walls to 

leach out from the grout. Some guard walls have just 

a few stones broken or missing, while parts of others 

have been sheared off or are leaning precariously 

over cliff s.

Entire sections of guard wall will have to be 

completely reconstructed in the most severe cases. In 

others, missing stones can simply be replaced. To meet 

current safety standards for guard wall height, either 

the walls will be raised or the road grade lowered.

For decades, fi nding a reliable and high-quality 

supply of historically compatible stone has been a 

challenge. Having assessed surrounding quarries, 

WFLHD and NPS currently are evaluating three 

possible sites with the required stone—Helena 

Formation limestone—with a preferred site expected 

to be chosen soon.

The Sun Road has 70 documented avalanche 

chutes where stonemasonry guard walls are 

susceptible to damage. Over the years NPS has 

installed various types of removable timber guardrails 

so avalanches pass over the road without causing 

damage. However, the original log rails of the 1930s 

were not crashworthy in that they did not withstand 

Over the years, avalanches, such as this one that took place on May 22, 2003, at Haystack Creek, have ripped up pavement, 

sheared off guard walls, and caused other road damage at 70 known avalanche chutes along the Sun Road.

NPS
9

vehicles hitting them and over time were found to 

crowd travel lanes as larger vehicles began using the 

road. Also, the high maintenance costs of removing 

the rails in the fall and reinstalling them each spring 

prompted NPS and WFLHD to seek other options.

Recent projects have used a new generation of 

removable guardrails that have been crash-tested 

and designed to protrude no farther into the travel 

lane than the guard walls. The new rails are more 

historically authentic and aesthetically pleasing to 

many than their predecessors.

New avalanche-resistant guard walls have been 

constructed with a reinforced concrete foundation 

and core, then fi nished with a historically compatible 

stonemasonry facing. A concrete slab anchored with 

small piles (micropiles) was laid within the roadway 

underneath the new guard wall, and 

the concrete colored to match the 

adjacent asphalt pavement. Two 

prototype guard walls performed well 

in a winter 2004 demonstration project, 

according to former WFLHD Project 

Manager Dick Gatten, who retired in 

January 2006. Each avalanche site, he 

says, will be evaluated to determine 

whether a resistant guard wall or 

removable guardrail will be installed.

Drainage. Many of the road’s 

original drainage systems are still 

functioning as designed, but some 

added after the road was paved in the 

1950s now suff er a variety of problems, 

from broken and separated pipes to 

crumbling stonemasonry headwalls. 

All historic structures slated for repair 

or rehabilitation will be designed with 

new drainage features to minimize 

water seepage and other damage due 

to the harsh climate. Structures not needing repair 

will have their drainage systems evaluated and rebuilt 

if necessary, with enlarged culverts.

Slope stability. Rockfall safety hazards are present 

along the steepest road sections because of unstable 

slopes and rock cuts, according to engineering studies. 

The roadway is also “creeping” (shifting) because of 

drainage problems, fi ll settlement, and avalanches.

Removing rockfall hazards within the original 

cut will involve selective rock scaling, the process of 

removing potentially loose and unstable slabs and 

outcrops before they crash down on the roadway. 

Those that are too large to scale will be bolted or 

anchored to more stable rock foundations. Also, to 

help support unstable rock, holes are drilled below 

the rocks that are to be stabilized; steel dowels are 

inserted; “shotcrete,” a type of concrete, is applied 

under pressure between the rocks and dowels; then 

the shotcrete is shaped, textured, and colored to match 

its surroundings. Slumping or creeping roadways 

will be evaluated and, if necessary, corrected with 

drainage improvements, retaining wall construction, 

reinforced earth, tieback anchors, and micropiles.

Pavement. The roadway in many locations has 

defi cient subgrade and road base, and along many 

other sections the surface is damaged and uneven. 

Solutions involve subexcavation to remove and 

replace unsuitable subgrade and road base material, 

as well as laying new pavement. Damaged or uneven 

pavement will be repaired and repaved. Remaining 

sections will be resurfaced. 

Masonry workers are attaching a historically 

compatible stone veneer to a new concrete retaining 

wall near Triple Aches.

As shown in this photo, more durable and longer-lasting reinforced concrete 

pavement is being installed in rockslide and avalanche-prone areas such as 

this site just east of Triple Arches.
10

SUCCESS STARTS WITH CAREFUL PLANNING

A project of this magnitude requires years of 

intense and collaborative planning. The process for 

completing the fi nal phases on a faster-than-normal 

schedule began in the mid-1990s, when NPS and 

WFLHD launched a retaining wall management 

program to identify, evaluate, and monitor the Sun 

Road’s 130 retaining walls. Having found serious 

structural problems in many of the walls, the agencies 

collaborated on various studies and initiatives in the 

late 1990s and early 2000s that led to the decision 

to rehabilitate the entire road—and as quickly as 

possible to prevent catastrophic wall failures and 

minimize impacts on the park and its visitors.

One initiative during the planning process 

involved forming a congressionally authorized Citizens 

Advisory Committee in February 2000 to help NPS 

develop initial alternatives that 

were considered in the project’s 

EIS. In addition to potential 

environmental and social 

impacts, the committee had to 

consider other issues, including 

project costs, scheduling, and 

historic preservation.

A major goal of the rehabilitation 

is maintaining the quality of the 

visitor experience, particularly during 

construction. Glacier is a worldfamous destination that accounts 

for much of the region’s tourism. A 

sudden dramatic drop in visitation 

because of intense construction along 

its most popular sightseeing route 

could result in undesirable economic 

consequences. The committee spent 

about a year and a half developing fi ve 

recommended alternatives. All but one 

of the alternatives were analyzed in the 

project EIS as follows.

Alternative 1: Repair as Needed or No Action.

Under this option, rehabilitation would continue as 

funding allowed over 50 years at an annual cost of 

$7 million to $8 million. Work would primarily focus 

on critical and emergency repairs without substantial 

long-range planning. This alternative was rejected 

because the badly needed repairs would not occur 

soon enough to preserve and protect the features 

and character of the Sun Road as a National Historic 

Landmark.

Alternative 2: Priority Rehabilitation.

Rehabilitation would occur over 20 years, with total 

funding at $157 million to $186 million, or about $8 

million to $9 million per year. The road would remain 

open to visitors, and a maximum cumulative delay 

The three orange safety markers demarcated 

a section of guard wall that has been sheared 

off by repeated vehicle impacts. This guard 

wall will be reconstructed with new and 

stronger footings and historically compatible 

stone.

Crews at the site shown here 

excavated the original retaining wall 

(at the far right) down to bedrock in 

preparation for reconstruction. They 

constructed a temporary retaining 

wall between the original retaining 

wall and the Jersey barrier to stabilize 

the work zone while they were 

reconstructing the historic retaining 

wall.

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11

of 30 minutes would be allowed when traveling the 

Sun Road’s entire length. This option would allow for 

advance planning to rehabilitate high-priority sites 

and would address current structural road defi ciencies 

but with only a few improvements to visitor facilities, 

such as turnouts, parking areas, and walkway access to 

interpretive sites. This option was not selected because 

repairs would not occur soon enough, resulting in 

continued road deterioration, loss of historic features, 

possible damage to natural resources, and greater 

economic impacts than Alternative 3. 

Alternative 3: Shared Use With Extended 

Rehabilitation Season. Rehabilitation would occur 

over 7 to 8 years at a total cost of $140 million to $170 

million, or about $18 million to $24 million per year, 

provided the needed funding would be available 

or unforeseen delays did not occur. This alternative 

would accomplish the needed road repairs while 

maintaining visitor use and access to the Sun Road. 

Roadwork would be conducted throughout the visitor 

season, but work requiring substantial traffi c delays 

would occur during the shoulder season, the time prior 

to mid-June and after mid-September. Otherwise, a 

maximum cumulative delay of 30 minutes would be 

allowed when traveling over the length of the road 

between mid-June and midSeptember, the peak season. 

Up to 1 hour of cumulative 

delays over the length of 

the road would be possible 

during nonpeak hours in the 

mornings (8 a.m. to 10 a.m.) 

and evenings (3 p.m. to 8 p.m.), 

Monday through Thursday. 

Variable traffi c delays would 

be used for night work, with 

advance notice to the public 

of the construction schedule.

Alternative 4: Accelerated Completion With 

Isolated Road Segment Traffi c Suspensions. The 

objective of this alternative would be to complete the 

rehabilitation as soon as possible by using isolated 

traffi c suspensions Monday through Thursday 

from the months of May through October. Visitor 

access would be maintained on the weekends. This 

alternative planned for repairs to be completed in 6 

to 8 years at a cost of $126 million to $144 million, 

or $16 million to $24 million per year. Alternative 4 

contained the same visitor use improvements and 

visitor development mitigation funding as Alternative 

3. Because of the faster rate of repair, Alternative 4 

would have minimized further deterioration to the 

Sun Road and historic, cultural, and natural resources. 

However, it would have the greatest impact on park 

visitation and annual impact on the local economy. 

Therefore, Alternative 4 was rejected.

PREFERRED ALTERNATIVE–OPEN FOR BUSINESS

During the EIS process, which included extensive 

public involvement through meetings, open houses, 

and a 60-day comment period, NPS and WFLHD 

selected Alternative 3 (Shared Use) as the best option. 

After some small changes, Shared Use was documented 

These renderings show the interior 

and exterior of a new transit center 

that will be constructed near 

Apgar Village at the park’s west 

entrance. This transit center, and 

another adjacent to an existing 

visitors’ center at the park’s east 

entrance, are part of a new Glacier 

shuttle bus system designed to 

minimize traffi c congestion during 

construction.

NPS

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12

and approved in the NPS’s ROD in November 2003 and 

WFLHD’s ROD in March 2004 because it provided the 

best balance of protecting historic, scenic, and natural 

resources while minimizing economic impacts.

Since the fi nal EIS and documentation in the 

RODs, the anticipated funding levels required to 

complete the entire repairs in 7 to 8 years did not 

become available. Consequently, NPS and WFLHD are 

jointly developing a strategy that will include public 

involvement and repair of the Sun Road in the earliest 

possible timetable, as available funding allows.

KEEPING BUSINESS AS USUAL

These strict road-closure limitations and the need 

to reduce traffi c congestion became the driving force 

behind development of a comprehensive mitigation 

program. How to keep 3,500 vehicles moving through 

a major construction zone every day on a narrow, 

steep mountain road without causing gridlock 

was one of the biggest challenges from the outset, 

according to Superintendent Holm. “During the next 

decade, visitors driving over the Sun Road are going 

to see more construction than normal,” he says. “So we 

needed to take measures to mitigate this. We want to 

make the driving experience as enjoyable and trouble 

free as possible.”

One of the fi rst eff orts toward this goal was 

completion of a construction sequencing strategy that 

details when and how all pieces of the rehabilitation 

puzzle will fi t together to minimize traffi c congestion 

and delays. The strategy calls for construction to 

progress generally from west to east where traffi c will 

be reduced to one lane most of the time. Temporary 

traffi c signals, vehicle-actuated devices set on fi xed 

cycles for times other than the actual work period, 

will be installed at each end of most work zones to 

control one-way traffi c. During the work periods, 

fl aggers usually will work in two-person teams, one 

THE BEGINNINGS OF CONTEXT SENSITIVE SOLUTIONS

A modern-day construction principle may be traceable specifi cally 

to 1924 and NPS. In that year, NPS’s fi rst director, Stephen Mather, 

sought help from BPR on Glacier National Park’s Transmountain 

Highway project, saying it warranted the “best engineers and the best 

landscape architects in the country.”

Under a January 1926 memorandum of agreement, BPR and NPS 

landscape engineers (landscape architects) worked together on road 

plans that blended the highway into the surrounding environment 

while meeting other objectives such as safety and capacity goals. “This 

is an early example of what is now called ‘Context Sensitive Solutions’,” 

according to NPS Landscape Architect Jack Gordon.

NPS Landscape Engineer Thomas Vint, who was associated with 

numerous park developments throughout his extensive career, wrote 

to NPS Chief Landscape Engineer D. R. Hull: “Construction details such 

as bridges, tunnels, retaining walls, parapets, culverts, etc., should not 

be monumental or stylistic but native, simple in line, and retiring.”

Bridges, retaining walls, and guard walls were all constructed of 

native rock excavated from initial road cuts and roadside quarries. 

Diff erent stone colors, including red and green argillites and buckskin 

limestone found along the alignment, were refl ected in adjacent guard 

walls.

This practice established a unique appearance and a precedent 

for other national parks to follow. It fulfi lled the desire of landscape 

engineers to “fi t foreign, manmade works as an inconspicuous, 

homogeneous part of the natural scenery,” according to Gordon. 

Other environmentally friendly practices included the requirement 

that contractors use the least destructive blasting techniques possible, 

and crews were prohibited from “side-casting,” dumping excavated 

materials over the roadside to the terrain below. Spoils were used 

as fi ll material whenever possible, and unsuitable material had to be 

properly dumped in designated locations.

This sensitivity to surroundings may be best expressed in the 

Triple Arches, arguably the most renowned structure along the 

Sun Road. Originally, Triple Arches was not even in the road’s plans, 

according to the Historic American Engineering Record, where NPS 

road records are archived. NPS and BPR originally wanted to bridge a 

gap in the mountainside at the site of Triple Arches by constructing a 

large retaining wall and building up the roadbed with huge amounts 

of fi ll material. But the contractor came up with the more innovative 

three-arch design.

A large retaining wall was originally planned for the 

site at Triple Arches, shown here. After construction 

started, the contractor obtained approval to build 

the more attractive triple-arch structure. But for all its 

engineering innovation, Triple Arches also mistakenly 

incorporated a design fl aw: The westernmost arch, on 

the far left, was built with its spring line—the imaginary 

line connecting the bottom of the two ends of the 

arch—parallel to the road’s 6-percent grade, rather 

than horizontally. This was corrected in the remaining 

two arches.

NPS archives
13

to control traffi c and the other to walk the lines of 

stopped vehicles to answer questions and provide 

information.

WFLHD is using a traffi c modeling computer 

program called QuickZone to predict traffi c impacts 

at each work zone. The program can estimate traffi c 

backups, delay times, and optimum construction 

schedules, and can estimate impacts resulting from 

construction schedule changes, fl aggers, and signal 

timing.

LEAVE THE DRIVING TO GLACIER

Another key component of the mitigation 

program is a new voluntary transit system. Visitors will 

still be able to drive their own vehicles over the road 

as usual, but they will have the option of leaving their 

cars at two transit centers—one at each end of the 

park—and taking regularly scheduled shuttle buses 

to the Sun Road’s most popular destinations, such as 

trailheads, overlooks, and interpretive sites. The system 

will be phased in over two seasons, with initial service 

covering a limited area starting in summer 2007 and 

the whole system scheduled to be fully implemented 

over the entire Sun Road by summer 2008. The transit 

center near the west entrance will be a new facility 

featuring a building where riders can obtain transit 

and road project information, a sheltered pickup 

and dropoff area for riders of the shuttle buses, and 

parking for about 150 vehicles. 

A Federal, State, and local partnership has been 

established to purchase and operate the shuttle bus 

fl eet during both the construction and off -seasons. 

The off -season program will help meet other Montanawide transit needs and make the entire transit system 

more cost eff ective. This partnership with the Montana 

Department of Transportation will leverage existing 

Flathead and Glacier County maintenance facilities, 

provide year-round employment in local gateway 

communities, and reduce the direct burden on FHWA 

and NPS for operating and maintaining the system. 

“We are really encouraging our visitors to use the 

transit system whenever possible, once it’s up and 

running,” says Superintendent Holm. “Our goal is to 

reduce vehicle traffi c on the Sun Road by 10 percent. 

If we can reach this goal, I think the driving experience 

will be enjoyable for everyone, whether you decide to 

drive, take an interpretive tour with either Sun Tours or 

aboard the historic red buses, or take a shuttle bus.”

SMART TRANSPORTATION SYSTEM

The entire Sun Road mitigation program will be 

supported by an extensive intelligent transportation 

system (ITS) computerized communications network 

that will provide real-time information to visitors 

regarding road conditions, parking availability, traffi c, 

weather, transit schedules, and more. For example, 

travelers planning a trip to Glacier, or en route to the 

park, will be able to receive construction information 

via the Internet, highway advisory radio, Montana’s 

511 telephone traffi c information system, and variable 

message signs strategically located inside and near 

the park.

Other features to enhance the visitor experience 

include new interpretive signs and exhibits at transit 

stops and other strategic locations that tell the 

story of the park’s history, wildlife, plant life, and 

the construction of the original Sun Road. Several 

locations will have interactive information kiosks.

In addition to ITS technologies and enhanced 

educational services, the mitigation program will 

mount a comprehensive public information eff ort, 

identifi ed by the advisory committee as an essential 

element in the Sun Road rehabilitation. This initiative 

will provide timely and accurate information through 

a variety of sources, such as the Internet, travel and 

tourism guides and magazines, the news media, 

brochures and signs at surrounding communities, 

gateway tourism and travel businesses, and public 

service announcements. The public information and 

outreach also will include customer service training 

for frontline employees about the project and related 

services.

The extraordinary eff ort that NPS and WFLHD 

are making to maximize the Glacier National Park 

experience throughout the entire construction 

project gives visitors added opportunities to witness 

history in the making -- the preservation of a national 

treasure.
14

A version of this article, titled “Saving a National 

Treasure,” was originally published in FHWA Public 

Roads magazine in the 2006 November/December 

issue. This article has been updated to provide 

recently available information about construction 

cost and schedule.

http://www.tfhrc.gov/pubrds/06nov/04.htm

Amy Vanderbilt is the public aff airs and outreach 

manager at Glacier National Park. She has been 

with NPS for 25 years, primarily in public aff airs and 

incident information positions at Glacier, Grand Teton, 

Yellowstone, and Yosemite national parks. She also 

served as a lead information offi cer for the NPS all-risk 

incident management team from 1995 to 1998. She 

can be reached at 406-888-7906 or amy_vanderbilt@

nps.gov.

Steve Moler is a public aff airs specialist at FHWA’s 

Resource Center in San Francisco. He has been with 

FHWA for 6 years, providing the agency’s fi eld offi ces 

and partners with support in media relations, public 

relations, and public involvement communications. 

He can be reached at 415-744-3103 or steve.moler@

fhwa.dot.gov.

The authors would like to thank Jack Gordon, Glacier’s 

landscape architect, for his substantial contribution to 

this article. For more information on the Going-to-theSun Road rehabilitation and road status, go to www.

nps.gov/glac/sunroad/whatsup.htm or www.nps.gov/

glac/montana.htm. The 511 Traveler Information and 

QuickZone are two of the FHWA priority, market-ready 

technologies, which are innovations that have proven 

benefi ts and are ready for deployment (see www.fhwa.

dot.gov/crt/lifecycle/ptisafety.cfm).
place cd on this page
Technical Report published by

Technology Deployment Program

Western Federal Lands Highway Division

Federal Highway Administration

610 East 5th St.

Vancouver, WA 98661

For more information or additional copies 

contact:

Amit Armstrong, Ph. D., P.E. 

Phone: 360.619.7668

Fax: 360.619.7846

Amit.Armstrong@fhwa.dot.gov

or

Amy Vanderbilt

Communications & Outreach Manager, 

Going-to-the-Sun Road Rehabilitation

Phone: 406-888-5838

Fax: 406-888-7907

Amy_Vanderbilt@nps.gov

Glacier National Park

P.O. Box 128 1 

West Glacier, MT 59936

Cover Images: Amit Armstrong, Ninh Phan, 

Cover Design: Sarah Wasill