Saw Mill Run Boulevard

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Saw Mill Run Boulevard

At Underwood Street

Smr at underwood 2.jpg

At Ivy Glen Street

SMR at Ivy Glen 1930.jpg

This is an online history of Saw Mill Run Boulevard (State Route 51):

Click here for the link to Saw Mill Run History

Saw Mill Run Boulevard

The Road:

Saw Mill Run Blvd. runs along the Saw Mill Run Valley. It begins at the intersection of Clairton Road and Provost Road at the City of Pittsburgh Line with Brentwood. It ends at the West End Circle at the entrance to the West End Bridge. A four lane highway for its the entire length, SMR consists of interchanges at the South Portal of the Liberty Tubes and with the Parkway West. It is an expressway from the Parkway to the West End Circle (West End Bypass). One of the well known traffic tie-ups in the area occurs between Maytide Street and PA 88 (Library Road) which is simply known as 'Maytide and 88.' Other Designations: Saw Mill Run Blvd. in its entirety is part of PA Route 51. It also is the route for US Truck 19 (West Liberty Ave. to Parkway West), and US 19 (West End Bypass). PA Route 88 was once signed on the highway until 1960.


Saw Mill Run Blvd. was part of the 1928 Allegheny County 'City Beautiful' bond issue. The bonds resulted in the creation of Saw Mill Run, Ohio River, Allegheny River and Mosside Boulevards. (1) After the completion of the Liberty Tunnels, Pittsburgh was officially accessible from the South Hills. As the South Hills grew, county and city planners looked for a road way that would "...tie together...eight important throughway and improved roads, (Library Road, Nobles Lane, West Liberty Blvd. or Old Washington Road [now W. Liberty Ave.], Banksville Road, Washington Pike, Noblestown Road, Steubenville Road and Carson Street.) " (2) It also was viewed as a way to bring the cities of McKeesport, Clairton and Duquesne closer to Pittsburgh. Construction began quickly and half of the roadway, from Library Road (PA 88) to near Knoxville, opened on December 1, 1929. (3) The roadway from Banksville Road to Knoxville opened in 1930. Shortly after the boulevard was open completely, local officials wanted to rename it 'Liberty Boulevard.' (4) This of course did not come to be.

Originally proposed by famed planner, Robert Moses, construction on the Saw Mill Run Extension (West End Bypass) began in 1949. The 1.1 mile expressway began at the Banksville Circle and ran to the West End Bridge. (5) The extension opened in 1951. The bypass would see an additional northbound lane built in the mid 90s to accommodate expected increases in traffic during the Ft Pitt Tunnels & Bridge rehabilitation.

The Banksville Traffic Circle (See Image #1) was eliminated during the construction of the Parkway West in the late 1950s. The circle was replaced with an interchange between Saw Mill Run Blvd/West End Bypass and the new highway. Later improvements in the 1990s and 2000s included median barriers from Whited St. to the Parkway. A new design at the Northern Terminus of the boulevard (See: West End Circle Improvements). A jughandle turning lane southbound at Woodruff St. A complete rehabilitation of the Library Road (PA 88) intersection.

Liberty Tunnel South Portal Interchange and SMR Expressway Plans: Even during the original construction of Saw Mill Run Boulevard, planners designed a complex interchange with the Boulevard, West Liberty Avenue, and the South Portal of the Liberty Tunnels. Nothing was done and again in 1950s, the state offered up plans for an interchange and a Saw Mill Run Bypass of the bottleneck at the tubes. (See Image #2) The interchange was also to be part of a Sam Mill Run Expressway that would widen the highway to six lanes, have controlled or limited access to side streets, and include various interchanges and connections to other proposed freeways. By this time, Saw Mill Run Blvd. was known more for its traffic headaches than its accessibility to the South Hills. From the mid 50s to the mid 70s, plans were introduced, changed, opposition and support was voiced, and in the end nothing was done.

It wasn't until the mid 1990s, and the impending doom of the closed Ft. Pitt Bridge and Tunnels, that talk of an interchange at the South Portal resurfaced. This time work actually began and was completed. In 1999, an interchange, a modified single-point diamond, was opened. Through traffic on Saw Mill Run Blvd. now rode over the intersection that once backed up traffic, sometimes for over a mile. The new interchange has been received warmly by commuters who no longer have to sit at the ancient traffic lights.

Other Proposals:

In the 1930's, Allegheny County attempted to purchase the Wabash Bridge and Tunnel as a way to alleviate traffic with the Liberty Bridge and Tubes. The move, attempted three times in the decade and spearheaded at times by Downtown Pittsburgh businessmen, failed on each attempt. One proposal, made in 1936, included an elevated traffic circle interchange that would involve: Sam Mill Run Blvd, the Wabash Tunnel Highway, and Woodruff St. (See Image #3). After a 1970s transit proposal known as Skybus went for naught, City of Pittsburgh Planners in 1986 considered converting the tunnel to a reversable one-way highway that would connect Saw Mill Run Blvd. to a parking facility at Station Square. (6) It wasn't until the 1990s when the fast approaching Ft. Pitt Bridge and Tunnel rehabilitation looming, that plans began to materialize to covert the tunnel to a legitimate link from Saw Mill Run into town. However, it wasn't until December 27, 2004, that the tunnel opened to traffic. The tunnel sits less than 1000' above the intersection of Saw Mill Run Blvd. and Woodruff St. For more information about the Wabash Tunnel Road Related Projects go here.


After being overlooked for decades, improvements are being made along the Saw Mill Run Corridor. New interchanges at the Liberty Tubes and West End Bridge, a center median reducing crossover crashes, improved intersections at Library Road and Woodruff Street are some of the current or completed projects in the area. Although not the expressway dreamed of in the 60s, transit options such as a total rebuild of the century old Overbrook Trolley Line, opening in 2003, and the 30 year old South Busway have eased some traffic woes.

However, Saw Mill Run Boulevard is still a very tight, traffic heavy, and dangerous road. A completed Saw Mill Run Expressway would have greatly improved traffic in the corridor. In Charlotte, North Carolina, the Independence (Blvd.) Freeway is a great look at what the Saw Mill Run Blvd. Expressway could have been. Part limited access and allowing some business and local road access, the Independence Freeway is a great improvement to residents east of the city. The six and sometimes eight lane highway, includes an independent bus-lane, interchanges with major roads, and a center median. The freeway is now being extended another mile and a half and will include a major interchange at Albemarle Road, a similar traffic situation to Maytide and 88.

And this is a nice link to the Liberty Tunnels: Liberty Tunnels History.