Mount Washington Roadway
(now McArdle Roadway)

McArdle Roadway passing under the Monongahela Incline.
McArdle Roadway passes under the Monongahela Incline on a foggy Pittsburgh morning. Photo by Dave DiCello.

History of Mount Washington (McArdle) Roadway

♦ Coal Hill
♦ Proposed Roadway
♦ Roadway Construction
♦ Bridge Construction
♦ Challenges Encountered
♦ Grand Opening

Lower Roadway Extension ♦
Renamed McArdle Roadway ♦
Recurring Landslides ♦
Upper Section Rebuilt ♦
Lower Section Rebuilt ♦
Restored to Original Beauty ♦

McCardle Roadway - August 1928
Mount Washington Roadway (now McArdle Roadway) along the Mount Washington hillside one month after opening in 1928.
From the Liberty Tunnels it rises to the concrete arch bridge, then under the Monongahela Incline. The road
continues up to the intersection of Grandview Avenue and Merrimac Street. Click on image to enlarge.

Coal Hill

Mount Washington, also known as Coal Hill, is a 600-foot mountain that hugs the southern banks of the Monongahela River. The northern face of the hill has, since before colonial times, been the most striking geologic feature of the three rivers area.

The Indians who inhabited the region before the arrival of the European settlers named the river "Monongahela," meaning the "river of sliding banks" in reference to the foreboding characteristics of Coal Hill.

Coal Hill - Mount Washington - 1888.
A 1888 picture showing Coal Hill, Mount Washington, towering over the Monongahela River. Forty years later,
the Mount Washington Roadway would scale the imposing hillside. Click on image to enlarge.

Atop the hill, directly across from Pittsburgh's Golden Triangle, are the present-day communities of Mount Washington and Duquesne Heights. As the City of Pittsburgh began to expand, this area became home to a large population of laborers that worked in the mills and factories along the Monongahela riverfront.

Running along the crest of Coal Hill is the scenic Grandview Avenue (once called High Street), a boulevard lined with homes, apartments, businesses and churches that offers a spectacular view of Pittsburgh's Golden Triangle and the Three Rivers.

Throughout the 1800's, as the city of Pittsburgh and the hilltop communities grew, one difficulty for residents was the lack of a quick and reliable transportation route from their homes to the bustling metropolis below.

Indian Trail Steps - 1910
The Indian Trail Steps in March 1910. Many hilltop commuters walked these city steps to and from work each day.

In the early years there was the Indian Trail, a steep and dangerous path down the north face of the hill. There was also the long and ardous southern route around Saw Mill Run to the West End. Beginning in 1870, inclines were built to facilitate travel for commuters.

At the dawn of the 20th Century, as the city expanded towards the south and the population continued to increase, the need for a direct roadway from Grandview Avenue to the South Side became a top priority for city officials.

Proposed Mount Washington Roadway

In 1912, led by City Councilman Peter J. McArdle, also a member of the City Planning Commission, a proposal for a thirty-foot roadway along the northern face of Coal Hill was introduced to Mayor Joseph Armstrong. The original cost estimate was $416,000.

With the full support of South Hills residents and the Board of Trade, a major bond issue was passed in 1919 to fund the construction of several new southern transit routes into the city.

In addition to the proposed Liberty Tunnels and Liberty Bridge, the bond issue also provided $700,000 for the construction of Mount Washington Roadway. The boulevard would extend from the intersection of Grandview Avenue and Merrimac Street, at the crest of the hill, to South Tenth Street on the South Side.

Construction of Mount Washington Roadway

The roadway was to be built in two phases. The first section to be completed would run from Arlington Avenue (then called Brownsville Road) to Grandview Avenue, intersecting near the bottom with the tunnel entrance. The second phase of construction would be a lower extension from Arlington Avenue to South Tenth Street.

The Liberty Tunnels, North Portal - 1925.
The northern outbound portal of the Liberty Tunnels in 1925. Work on the Liberty Bridge was beginning and soon
Mount Washington Roadway construction would start. When the intersection was completed in 1928,
a decorative traffic circle was installed to facilitate the four-way flow of vehicles.

The Liberty Tunnels opened in January 1924, giving South Hills residents their first direct route through Coal Hill to the city. Work then began on the Liberty Bridge, which would carry traffic across the Monongahela River to downtown Pittsburgh.

In 1925, starting near the northern portals of the tunnel, construction began on Mount Washington Roadway. The challenges of scaling the sometimes cliff-like hillside would be no easy task, requiring every bit of engineering expertise available at the time.

Excavating under the Monongahela Incline - 1926
Excavating a path under the Monongahela Incline in December 1926.

Mount Washington Roadway at Merrimac Street and Grandview Avenue - 1927
The Lash Real Estate office, located on Grandview Avenue across from Merrimac Street, shown here
in 1927, was razed to build the upper entrance to the Mount Washington Roadway.

By the time construction commenced, the estimated cost of the roadway had risen to nearly $1,250,000, a half million dollars more than provided for by the 1919 bond issue. Because of this, work was halted for two years until the necessary finances were obtained.

Bridge Construction

Work resumed in mid-1927 with the construction of the Mount Washington Roadway Bridge. The concrete arch span crossed the valley where the Castle Shannon Incline was located. The bridge was completed in June 1928, but not without concern over the discovery of numerous structural defects, leading to major delays.

Construction of Mount Washington Roadway Bridge - 1927    Construction of Mount Washington Roadway Bridge - 1927

Construction of Mount Washington Roadway Bridge - 1927    Construction of Mount Washington Roadway Bridge - 1927

Construction of Mount Washington Roadway Bridge - 1927    Construction of Mount Washington Roadway Bridge - 1927

Construction of Mount Washington Roadway Bridge - June 1928
Several photos showing the construction of the Mount Washington Roadway Bridge. The final picture shows
the bridge in June 1928, one month before the grand opening of the million-dollar boulevard.

Challenges Encountered

Shortly after the concrete was poured in the bridge's foundation and lower arch supports, cracks began to form. After careful inspection by engineers from the Mellon Institute, it was discovered that sub-standard concrete was used and that it was not properly poured, leaving a honeycomb of voids in the foundation. These problems were addressed by the contractors.

Pittsburgh Press illustration - March 2, 1928

The image above appeared in the March 2, 1928 Pittsburgh Press. The caption read:

"Here are some views of the concrete bridge over the Castle Shannon Incline, a part of the Mount Washington Roadway and now the subject of discussion by city officials as the result of poor concrete work. The large photo is a general view of the bridge, while at the top left is a close-up of some patch work apparently done to hide honeycombs. Bottom left is another close-up of one of the defects, a patch and a huge crack. Some of these cracks, according to reports made to Councilman Malone, extend completely through the work. At the right is a spot in the bridge that is apparently a bad defect, a hole where the concrete has completely cracked out or has been taken our for some unexplained reason."

Construction of Mount Washington Roadway - 1927.    Construction of Mount Washington Roadway - 1927.
Contactors working on the construction of the roadbed along Mount Washington Roadway.

Other obstacles encountered during the construction of the roadway were the abundant mine shaft openings along the route, and the sheer cliff surface near the top. The mines were filled in and sealed, and excavations were done along the route to provide as much of a solid, level roadway surface as possible.

In some locations was not practicable, especially near the top. The solution was to construct a bridge along the upper portion of the roadway that jutted out from the cliff face, supported by concrete piers and steel beams drilled into the hillside.

Mount Washington Roadway at Merrimac Street and Grandview Avenue - 1937
The upper entrance to Mount Washington Roadway along Grandview Avenue at Merrimac Street, shown here in 1937.

Despite the numerous challenges, Mount Washington Roadway was completed in a little over one year. The surface was fifty feet in width including the pedestrian sidewalk. The road was covered in paving bricks from Arlington Avenue to the upper abutment of the arch bridge. The remainder of the roadway to Grandview Avenue was paved in concrete.

Grand Opening - July 17, 1928

Measuring nearly one mile in length and costing just over $1.1 million, the new boulevard was dedicated on July 17, 1928. Along with the March 1928 dedication of the Liberty Bridge, hilltop residents celebrated the beginning of a new age of quick and easy transportation to and from the heart of the City of Pittsburgh.

Mount Washington Roadway Dedication - July 17, 1928
On July 17, 1928, the ribbon was cut for the new Mount Washington Roadway was done by Betty Keefer and
P.J. McArdle Jr.. Also pictured are (left to right): Councilmen Robert Alderdice and John Herron, Samuel
Reno, Councilman Daniel Winters, President of Council Joseph Malone and Councilman Peter J. McArdle.

Mount Washington Roadway Dedication - July 17, 1928
Spectators watch the first car to travel Mount Washington Roadway.

When first opened, Mount Washington Roadway was considered a monument to engineering genius. Because it was designed to hang from a cliff with a long history of landslide activity, there was considerable skepticism as to whether it would last long before tumbling towards the Monongahela River.

The Northern Portals of the Liberty Tunnels
and the traffic circle in November 1932.
The northern portals of the Liberty Tunnels and the traffic circle at the intersection with Mount Washington Roadway,
shown here in 1932. The following year, due to increasing traffic congestion, the traffic circle was removed.

Mount Washington Roadway Extension

Immediately after the opening of the upper section of Mount Washington Roadway, planning and preparations began on the lower extension that would take the roadway through to the South Side. This would require the demolition of several homes along the proposed route, as well as the construction of two viaducts and a small bridge.

Construction of Lower Mount Washington Roadway Viaduct - 1929    Construction of Lower Mount Washington Roadway Viaduct - 1929
South Side homes along the proposed route of Viaduct #1 (left) and Viaduct #2 (right), shown in 1929.

Construction of Lower Mount Washington Roadway Viaduct - 1931
Homes along Manor Street, near the Liberty Bridge, that were razed for the construction of Viaduct #2.
Many of the foundations of these homes are still visible along the hillside next to the viaduct.

By May 1932, the city had spent $250,000 purchasing the land and razing homes along the proposed route. Another $900,000 would be spent on the viaducts and roadway construction.

From Arlington Avenue, the 372-foot Viaduct #2 was constructed to carry the roadway over the Arlington ravine. After a sharp turn to the right, the twenty-six foot wide roadway hugged the hillside, supported by nine spans of steel trussed bents until it reached the Pennsylvania Railroad tracks. The route also included was a six-foot sidewalk.

Lower McCardle Roadway Bridge Drawing
A schematic drawing showing Viaduct #1 and the accompanying bridge over the Pennsylvania Railroad tracks.

Construction of Lower Mount Washington Roadway Viaduct - September 1932    Construction of Lower Mount Washington Roadway Viaduct - October 1932
The 1932 construction of Viaduct #2 at the intersection with Arlington Avenue (left) and one of the concrete
piers of the bridge that would carry the roadway over the Pennsylvania Railroad tracks.

Construction of Lower Mount Washington Roadway Viaduct - June 1933    Construction of Lower Mount Washington Roadway Viaduct - July 1933
Construction of Viaduct #1 in the summer of 1933.

Construction of Lower Mount Washington Roadway Viaduct - June 1933>
The through-truss bridge over the Pennsylvania Railroad tracks and Viaduct #1, shown in October 1933.

A 215-foot through-truss bridge carried the road over the Pennsylvania Railroad tracks and onto Viaduct #1, which ran a further 541 feet on eleven spans of steel trussed bents. The roadway reached ground level at South Ninth Street and continued another city block until it intersected with South Tenth Street.

Construction of Lower Mount Washington Roadway - October 1933
The entrance to the lower extension of Mount Washington Roadway at Arlington Avenue in October 1933.

The Lower Extension opened to traffic in late-October 1933. Construction of the entire Mount Washington Roadway took twenty-one years to accomplish since the concept was first proposed by Councilman McArdle in 1912. When finally finished it provided the hilltop communities with a major transportation route to both the city and the South Side industrial complex.

Renamed McArdle Roadway

P.J. McArdle was a career politician that held the office of City Councilman for four separate terms (1911-1913, 1916-1919, 1922-1930, and 1932-1940). A long-time Mount Washington resident, McArdle died while in office on January 1, 1940.

Soon after his death, a motion was advanced to rename Mount Washington Roadway after McArdle, one of the first city officials to champion the idea of the hillside boulevard.

P. J. McArdle.

The effort was led by his son Joseph McArdle, a State Legislator who went on to become Pittsburgh City Councilman from 1942 to 1949. The motion was eventually accepted, and in 1943 the iconic boulevard was renamed P.J. McArdle Roadway.

It has retained that designation ever since. In 1984, a motion was advanced in City Council to rename the boulevard back to Mount Washington Roadway, but these efforts failed.

Landslides and the Ravages of Time

Over the next several decades, McArdle Roadway served the city well. Despite initial fears of the upper section tumbling towards the Monongahela River, the roadway clung to the hillside and remained a vital part of the Pittsburgh transportation network.

Due to the many fissures in the rock face and the geologic instability of Coal Hill, falling rocks and occasional landslides were a constant challenge to city engineers. Efforts were made over the years to stabilize portions of the hillside to keep the roadway in continual service.

Landslide near the top of McArdle Roadway - 2012.    Landslide along McArdle Roadway
Landslides have been a recurring problem along the Mount Washington slopes.

In 1950, the upper portion of McArdle Roadway was rehabilitated and repaved entirely in asphalt. Ten years later, in 1960, the lower extension was closed for repairs to the aging viaducts and bridge. The road surface of the lower section was also coated in black top.

The challenges of keeping the roadway in functioning condition in the years that followed were many. The rock slides persisted, and the aging infrastructure was badly in need of extensive reconstruction. Finding the necessary funding proved a major hurdle.

The intersection of McArdle Roadway
and Arlington Avenue in 1971.
The intersection of McArdle Roadway and Arlington Avenue in 1971.

By 1979, the roadway surface and supporting bridges on the upper section, from the tunnels to Grandview Avenue, had deteriorated to the point that traffic restrictions were put in place. The two-way roadway was limited to one lane in either the inbound or outbound direction. Heavy vehicles were banned for fear that they would crash through the bridge decks.

Upper Section of Roadway Rebuilt

Finally, in 1982, with the help of Federal Highway Grants, the upper section of McArdle Roadway was closed for a thorough rehabilitation. This effort included the demolition of the old Mount Washington Roadway Bridge and construction of a new span over East Sycamore Street. The upper roadway, including the entire cliffside bridge, would also be rebuilt, along with other infrastructure improvements.

The project began on April 12, 1982. The first phase of the reconstruction was demolition of the concrete arch bridge and erection of a new span. This was completed in November 1983, allowing for the temporary reopening of the roadway for the holiday season.

McArdle Roadway Bridge
The new McArdle Roadway Bridge was completed in November 1983.

In January 1984 the road was again closed for the comprehensive rebuilding of the upper section. Along this section of the boulevard, a retaining wall was built, then backfilled. This created a solid foundation for a new road bed and eliminated the need for the majority of the overhanging bridge.

During this phase of the project, engineers encountered several more abandoned mine shaft openings that had to be filled and sealed. Concrete sealant was also plastered over other portions of the hillside where large fissures were present.

Monongahela Incline over McArdle Roadway.
Pittsburgh's historic Monongahela Incline passes over a snow-covered McArdle Roadway.

The entire reconstruction effort was completed in April 1985 at a cost of $7 million. When the roadway was opened to traffic, the results were magnificent and cause for celebration amongst hilltop businesses and residents, who had endured over six years of disruption.

Although falling rock and landslides continue to challenge the Public Works engineering department, forcing temporary closures, McCardle Roadway remains one of the city's most heavily traveled arteries, especially during the morning and afternoon rush hours.

A rockslide on McArdle Roadway    a fallen tree along McArdle Roadway
Pittsburgh Public Works crews work diligently clearing falling rocks, trees and other debris from McCardle Roadway.

Lower Extension Undergoes Comprehensive Rehabilitation

The lower extension, from Arlington Avenue to South Tenth Street, was closed off and on beginning in 2007 for much needed repairs to the viaducts and bridge, costing the city $300,000. Rated structurally deficient after over seventy years of service, this vital connector was permanently closed in January 2011 for a comprehensive refurbishment when federal funding was obtained.

Lower Mount Washington Roadway Viaduct - 2007    Lower Mount Washington Roadway Viaduct - 2007
The bridge over the railroad tracks, shown in 2007, had deteriorated and was badly in need of repair.

Viaduct #2 was completely replaced. The bridge over the railroad tracks, and Viaduct #1, were both rehabilitated and reinforced. The entire sidewalk and roadbed decking were replaced and the steel girders repainted in their original green color.

Lower McArdle Roadway
The refurbished bridge and the road surface of Viaduct #1 in August 2012.

This section of McArdle Roadway reopened to traffic on August 22, 2012. The $10 million project reconnected the South Side with the Liberty Bridge and Mount Washington, allowing residents to easily commute to and from the flourishing neighborhood business districts.

Roadway Restored to Original Beauty

Once again, the entire stretch of the McArdle Roadway was open to unrestricted vehicular traffic. In addition to the transportation benefits to residents of the South Side, Mount Washington and the South Hills, the roadway provides a scenic route for tourists and other city dwellers on their drive to the many popular destinations located around Pittsburgh.

McArdle Roadway
A vehicle heading up McArdle Roadway towards Grandview Avenue and Mount Washington.

McArdle Roadway heading up towards
the Monongahela Incline.    McArdle Roadway heading down
from near Grandview Avenue.
Ready to pass under the Monongahela Incline tracks (left) and heading down from near Grandview Avenue.

McArdle Roadway in the wintertime.
Looking up along McArdle Roadway after a storm blanketed the trees in fresh coating of snow.

From vantage points all along the hillside boulevard, motorists and pedestrians can gaze out at the breathtaking vista of Pittsburgh's Golden Triangle and the Three Rivers.

McArdle Roadway, formerly known as Mount Washington Roadway, is one of the many remarkable features that make up the landscape of the City of Pittsburgh. And, as profoundly proclaimed back in 1928, it is a historic monument to engineering genius.

The City of Pittsburgh from the top of McArdle Roadway.
A view of downtown Pittsburgh from a Grandview Avenue lookout, showing McArdle Roadway in lower right.

The Pittsburgh Skyline from McArdle Roadway.    The Pittsburgh Skyline from McArdle Roadway.
Two view of the Pittsburgh skyline from the upper sidewalk along McArdle Roadway, near Grandview Avenue.

The City of Pittsburgh from Viaduct #1.
A view of the City of Pittsburgh from Viaduct #1 on Lower McArdle Roadway in 2002.

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