In 1928, the route was under construction from Laurel Hill Road to Flatwoods Road and Nichols Hill Road to current PA 201 and completed the following year.  In 1929, the route was moved from Montour Street, Ewings Mill Road, Forest Grove Road, Pine Hollow Road, and Broadway between Coraopolis and McKees Rocks to the current alignment.

In 1930, the route was paved from current PA 201 to current PA 136.  Also that year, the first section of Saw Mill Run Boulevard opened from Brownsville Road to the Liberty Tunnel.  The designation was moved off Brownsville Road and Arlington Avenue onto the new highway and through the tunnel to the P. J. McArdle Roadway to keep the route complete.  In 1933, the rest of it to Woodville Street opened and the designation placed on the boulevard.  In 1934, the section from Desiderio Boulevard to West Elizabeth was under construction, and opened the following year.

In 1946, the route was moved off Taggart Road in Beaver County.  In 1949, construction began on a bypass west of Perryopolis from Star Junction to Wickhaven, and was widened from PA 201 to Star Junction.  The bypass opened in 1950.

In 1952, the West End Bypass opened to traffic from the Penn-Lincoln Parkway to PA 837.  However, the PA 51 designation still followed Woodville Street and Wabash Street to the West End Circle until 1955.  In 1953, the designation was moved out of Darlington onto a new alignment south.

Work to widen and install a median began in Wickhaven and at PA 201 in 1958.  A median was installed in 1958 between Braden Road and PA 251.  The following year medians were installed between Star Junction and north of Uniontown at the US 119 interchange.

A median was installed in 1960 between PA 201 and PA 48.  In 1961, construction started on a new alignment from I-70 to PA 201, and opened the following year.  A median was installed in 1962 from I-70 to Wickhaven.  In 1967, the rest from Wickhaven to PA 201 was done.

In 1976, the route was changed to its current alignment between Stoops Ferry and Monaca.  Previous to that, it turned onto Narrows Run Road, then Brodhead Road to PA 18 and back to its current alignment in Monaca.

In 1997, construction began on the interchange at the southern portal of the Liberty Tunnel, and opened to traffic on November 20, 1999.

If you drive PA 51, you know the intersection at PA 88 and Maytide Street can be a nasty bottleneck.  However, PennDOT is exploring making changes at that intersection.  The varying plans call for building an interchange all the way to keeping the at-grade intersection but improving it with jughandles to eliminate left turns.  Whatever is chosen as the final building option, the work will not begin until 2008 at the earliest.

In 1930, the route was paved from Stoyestown to Hollsople, Ashville to Frugality, and Brook to now SR 3011 was paved.  In 1931, the route was under construction from Gallitzin to Ashville and completed the following year.  In 1932, the northern terminus was moved from Reedsville to Potters Mills.  Also the section in Kantner was paved as well as from Blough to Landstreet.

In 1967, the northern terminus was moved from US 322 in Potters Mills to its current location.

In 1970, the southern terminus is moved from the Maryland state line to US 219.  Traversed Johnstown on Napoleon Street, Somerset Street, Franklin Street, Main Street and left via Frankstown Road.  Southbound traffic Adams Street, Bedford Street, and Vine Street.

In 2004, the entire route was placed on Center Street in its entirety in Phillipsburg, instead of splitting traffic between it and Front Street.

In 1930, the route was paved from the Mayberry Township line to the Susquehanna River, Mausdale to Hillside Road, and from Washingtonville to the current PA 44 intersection.  In 1932, the route was paved from Lorson Road to PA 554 and from Elysburg to Atlas.  In 1936, the route was moved off the current PA 44 alignment between Jersey Shore and Turbotville and the western terminus moved to US 15 at the Susquehanna Trail.  Ten years later it was moved beyond that point to its current location near Montgomery.

In 1961, the eastern terminus was moved from Ashland to Mausdale replacing the PA 45 designation and signed on Ashland Road between Mount Carmel and Ashland.  In 1966, the eastern terminus was moved from PA 642 in Mausdale to its current location using the old PA 45 alignment between Mausdale and Mt. Carmel and Ashland and Nesquehoning.

A median was installed in 1971 from Danville to Interstate 80.  In 1992, cracks developed south of Centralia, and eventually the highway was closed.  The road was shut down in early 1994.  In 1999, the route was changed to bypass Centralia after years of the underground mine fire taking its toll on the highway.  The route was changed to follow SR 2035, PA 901, SR 2042, SR 3002, and SR 4028 to rejoin its former route along PA 61.

In 1930, the route was moved from Iron Street, Walnut Street, and Main Street to Front Street, John Street, and Vine Street.  In 1932, the route was paved from Shady Plain to Jacksonville Road.

In 1951, construction began on a new alignment from Shearersburg to PA 356 and opened the following year.  In 1959, the highway was widened and a median installed on it from Leechburg Road to Melwood Road.

Until 1960, the route was came in on Johns Street and Vine Street into Johnstown.  Then the route was on Washington Street, Johns Street, Main Street eastbound, Vine Street to Roosevelt Boulevard westbound, and on Bedford Street.  In 1960, work began on the section from PA 601 to east of Rummel, which opened in 1961 and included widening and dividing from Geistown to PA 601.  Also in 1961, a new alignment from New Kensington to Leechburg Road opened and moved the designation from going through Lower Burrell and Arnold on Locust Street, Freeport Road, and Leechburg Road to the current alignment.

In 1964, the eastern terminus was moved from Cessna to its current location.  In 1965, the route was moved onto the Johnstown Expressway from the Widman Street interchange to US 219 and down that expressway to Scalp Avenue when that section of expressway was completed.

In 1971, a new alignment opened from Vandergrift-Leechburg Road to Vandergrift.  Previously it continued on PA 356 to Labelle Vue Road, Holland Street, Longfellow Street, and Alternate PA 66.  That same year construction was extended from the Bedford Street interchange to Roosevelt Boulevard.  In 1972, the section from the Widman Street interchange to the Bedford Street interchange opened to traffic.  Construction finished on the section of Johnstown Expressway from Somerset Street to Dale in 1973, and with that, the designation was moved onto the new highway and Roosevelt Boulevard.

The Johnstown Expressway became a victim of the 1977 Johnstown Flood, when at 2:00 AM on July 20, runoff from Solomon Run cut the Widman Street exit ramp in half.

When the final section of the Allegheny Valley Expressway between Exit 13 and Exit 15 opened in 1985, and PA 28 moved onto it from Freeport Road, PA 56's western terminus moved from that intersection across the New Kensington Bridge to the current terminus at Industrial Boulevard.

In 1997, the route changed from the path it took from Shady Plain to Homer City via West Lebanon and Edgewood to the current path.  The new route created several new multiplexes, with the most unusual with PA 156 from South Bend to Shelocta where that highway has its terminus.  The original route is not forgotten as it is named Old Route 56 Highway West in Indiana County where it is SR 3056, and in Armstrong County where it is SR 2056.

With PennDOT restructuring their 12-Year Transportation Program, two projects along PA 56 are now in jeopardy.  The first is the relocation of the alignment near Pleasantville in West St. Clair Township to eliminate the hairpin curve locally referred to as the “Peggy Westover Curve."  The section was studied in 1995 with bid letting in 2007, but now the project has moved into the reevaluate column.  The second project which would involve a realignment of the route in Johnstown's West End has been deferred.

In 1941, the eastern terminus was moved from US 6 in Port Allegheny to its current location.  In 1952, the route was changed to its current alignment between Marshburg and Ormsby.  Originally, it used the PA 770 and PA 646 alignment.

In 1964, work a new alignment between Kinzua Heights and Marshburg began due to the creation of the Allegheny Reservoir.  A year later, that section opened to traffic. Prior to that, the route went north from near Kinzua Heights to Cornplanter which is now a branch of the reservoir, then in a southeastern direction to Marshburg over what is PA 321.

I-79 to I-376/US 22/US 30

Signed in 1956.  In 1962, the northern terminus was moved from US 22/US 30 to PA 51 in Carnot.

Conceived in the 1963 Pittsburgh transportation plan, this expressway was built to connect the downtown area to the suburban areas to the west and northwest of the city.  Construction began in 1965 from the West Middlesex interchange to the PA 18 interchange.  The following year construction commenced on the Vanport Bridge over the Ohio River and opened the following year.  In 1968, the first section opened to traffic from the West Middlesex interchange to the PA 18 interchange opened to traffic and received the PA 18 designation, as it created a bypass around West Middlesex.  That same year, construction began on the section from Exit 9 to Exit 12.  In 1969, construction began on the section from Exit 13 to Exit 14 while construction was extended from Flaugherty Run Road to Exit 9.

The 1970s began with construction starting in Lawrence County on the section from the current PA Turnpike 60 interchange to Mitchell Road in 1970.  In 1971, the second section of the expressway opened to traffic from Flaugherty Run Road to Exit 12.  That same year, construction was extended from Exit 14 to a half-way point between the exit and PA 51 and the following year it was extended to near PA 51.  In 1972, the section from Exit 13 to Exit 14 opened to traffic and with that the route was moved from ending at PA 978  to ending at Exit 14.

In 1973, the section from the current interchange of PA Turnpike 60 to US 224 opened to traffic, while construction began on the section from that interchange to north of the town of Pulaski.  Construction was extended to PA 51 from Exit 14 in 1974 and in 1975, construction was extended from north of Pulaski to the West Middlesex interchange.  In 1976, the section from Exit 10 to Exit 29 at PA 51 was completely open to traffic and created what would become the end of PA 60 for almost two decades at PA 51.  In that same year, the section from US 224 to Mitchell Road opened as well.  The following year the expressway would from Mitchell Road to PA 18 and signal the completion of the Beaver Valley Expressway minus the section from PA 51 to US 422.  In 1978, the PA 18 designation was moved back to the original route through West Middlesex.

June 14, 1990 marked the beginning of the end for the "missing-link" between PA 51 and US 422.  Built and maintained by the Pennsylvania Turnpike Commission, this section opened from PA 108 to US 422 on November 8, 1991 and the rest of the expressway on November 20, 1992.  That same year, the northern terminus was moved north from I-80 to PA 18, and then seven years later, moved to its final location at Business US 62 in Sharon.

Construction began on the newest part of PA 60, the Southern Expressway, in 1990 to serve the new Midfield Terminal of Pittsburgh International Airport.  This 7.5 mile, $190 million section opened to traffic in September 1992.

On October 17, 2005, US Senator Rick Santorum and US Representative Melissa Hart made an announcement at Pittsburgh International Airport that had been years in coming.  On November 6, 2009, the Interstate 376 designation officially replaced PA 60 from US 22/US 30 to PA 18. 

The route was decommissioned when PA 60 was decommissioned north of the US 22/US 30 cloverleaf and replaced by Interstate 376.

Signed from 1928 to 1936 from Concordville to Chester on Concord Road, Chelsea Road, and Chinchester Avenue in Delaware County.

Signed in 1963 on its current alignment.  In 1983, the route suffered severe subsidence damage in the form of cracks from the Centralia mine fire south of the borough.  The Pennsylvania Department of Environmental Resources paid $500,000 to stabilize the roadway.  In 1987, the Saint Clair bypass was completed and moved traffic out of the borough.

Until 1991, the northern terminus was located at PA 147 in Sunbury.  It was moved to its current location after the new Veterans Memorial Bridge was completed.

In 1992, it was determined that the roadway south of Centralia was beyond repair, and eventually the highway was closed in early 1994.  The PA 61 designation was detoured on the current PA 54 alignment between Ashland and Mount Carmel.  In 1999, the adjacent Byrnesville Road, which carries the SR 2002 designation, was upgraded and now bypasses a section damaged by the underground mine fire that has been burning in Centralia since 1962.

In 1930, the route was paved from Trexlertown to Fogelsville and Claussville to Holbens Valley Road.  SR 0062 is currently assigned to US 62.

In 1934, the section from Beech Creek to Lusk Run Road was under construction and opened the following year.  In 1935, the route was moved to Lusk Run Road.

In 1946, the route was placed on its current alignment between Zion and Mill Hall.  Previous to this, it ran between Milesburg and Mill Hall on what became US 220.

Southern terminus moved from Dale Summit to Zion in 1973.  The northern terminus was moved from Cedar Springs to Mill Hall in 1978.

Signed in its current location in 1961.  A median was installed in 1965 between Rochester and Freedom.

Construction would being on the next section of Ohio River Boulevard from near the California Avenue/Marshall Avenue intersection to Pennsylvania Avenue in January 1970.  In 1973, this $16 million section opened to traffic with plans to continue the expressway to the Fort Duquesne Bridge.

With traffic increasing on the North Shore, construction on the $8 million Phase One project to connect the two sections of Ohio River Boulevard together began in Spring 1987 from Allegheny Avenue to Western Avenue.  Phase Two of the project would begin in January 1988, which would consist of a new interchange between the expressway and the West End Bridge.  The bridge would be closed for two years while it underwent rehabilitation and new ramps were built at the northern end for the interchange.

In 1992, the southern terminus was moved from Western Avenue to I-279 when the missing-link in Ohio River Boulevard was finally closed.

If you were a daily commuter who used Ohio River Boulevard in the later half of the first decade of the 21st Century, you have my sympathy.  Due to construction of a Super Walmart on a hillside where Dixmont State Hospital once stood overlooking PA 65 in Kilbuck Township, landslides started to become a common occurrence.  The first landslide happened on April 27, 2006 after blasting loosened the soil and caused a road closure for two days, but then another happened on September 19 where an estimated 300,000 to 500,000 cubic yards of earth buried the roadway and adjacent Norfolk Southern Railroad tracks.  That last one prompted the Department of Environmental Protection to force Senex Explosives to submit blasting plans before blasting; however, two of the four lanes of the roadway would remain closed for another three years.  Repair work began on June 8, 2009 but had to be halted due to discovery of a damaged footer that supported the median barrier.  Upon PennDOT's review of the plans and approval, work resumed in July with the southbound lanes reopening on August 3, 2009 and the northbound lanes later in that same month.  Due to the unstable nature of the hillside, Walmart withdrew plans for their store in 2007 but assumed responsibility for ongoing maintenance of the site.

In February 2007, the northern terminus was moved from Business US 422 to PA 108/PA 168 at Croton Avenue in New Castle.

In 1930, the section from West Virginia to Greensburg was decommissioned in favor for the new US 119 route.  In 1932, the northern terminus was moved from the New York state line to Frysburg.  In 1935, the northern terminus was moved from Fryburg to Tionesta.

Construction on the US 22/PA 66 cloverleaf finished in 1958.  It was replaced with a SPDI in 2000 as part of the US 22 rehabilitation.  In 1959, the route was widened from Greensburg to Clopper Street and a median installed from US 22 to north of Delmont and PA 286 to north of PA 366.  

In 1960, the designation was moved from Courthouse Road to bypass Kittanning on its current alignment.  In 1968, route moved onto I-80 to bypass Clarion and onto its current route between Clarion Junction and Kane.  That same year, the northern terminus was moved from Tionesta to its current location.  A median was installed in 1982 from Ford City to US 422.

Construction began on the Amos K. Hutchinson Bypass in August 1990, with the part from US 119 to US 30 opening on July 13, 1993.  The remaining section to US 22 opened on December 9, 1993.  With that, the southern terminus was moved from Otterman Street in Greensburg to its current location.

Construction began on March 24, 2000 to finish the Kittanning Bypass.  This section opened to traffic on December 13, 2001.

On May 19, 2003, during a "Click It or Ticket" blitz, a police officer handing out  flyers to drivers on North Main Street near Cabin Hill Drive noticed two men, later determined to be Mexican, sitting up front in the truck were not wearing seat belts. They were told to pull over.  A search of the truck found five other Mexican men lying side by side in the back, concealed by tinted windows. Two women were riding behind the front seats.  None of the occupants spoke English.

In 1956, eastbound traffic was moved to Cunningham Street and McKean Street in Butler.

In 1962, the northern terminus was moved from Kinzua, which is now under the Allegheny Reservoir near Kinzua Heights, to Kane.  In 1968, the northern terminus was moved from Kane to its current location.

At 10 AM on June 4, 2007, the 122-year-old East Brady Bridge that spanned the Allegheny River between Brady's Bend and East Brady, was demolished by explosives.  It had been replaced by a span 300 feet downstream named the Sergeant Carl F. Curran II Bridge which opened on April 26.  It is named in honor of a native of East Brady who was killed near Fallujah, Iraq in 2004 while serving with the Pennsylvania National Guard.

In 1946, the route was moved from Reservoir Street from US 6 to Simpson to Belmont Street.  That year the northern terminus was moved from Susquehanna to the New York state line.

SR 0070 is currently assigned to Interstate 70.

In 1955, the route was moved onto the new expressway from PA 481 to PA 88, from what is currently SR 2016 and Lincoln Avenue from PA 481 to Charleroi.  In 1960, the eastern terminus was moved from the intersection of West Pittsburgh Street and West Newton Street to US 30.

In 1932, the route was paved from Jonestown to PA 343.  In 1936, the northern terminus was placed at its current location from Lancaster Street at PA 343 north of Jonestown and the southern terminus placed in Goshen.

Until 1946, there was another PA 72 from US 11 to US 309 on Bridge Street, Carey Avenue, River Street, and South Street in Wilkes-Barre.

In 1958, the route was placed on Queen Street for northbound traffic in Lancaster.  Southbound traffic was moved onto 10th Street in Lebanon and a median was installed from Jonestown to Interstate 78 that year.

In 1965, the southern terminus was moved from Goshen to its current location.

In 1970, replaced PA 934 from PA 443 to Lickdale to end at that route.  Six years later, the route's northern terminus was moved to Lickdale.

In 1991, the section that comprises the Cornwall Bypass was upgraded to expressway standards.  In 1995, the current northern terminus was selected.

A year later, PennDOT studied improving the route between PA 283 and the PA Turnpike.  It concluded that left turn lane/shoulder improvements, widening, and “relief routes” around the boroughs of East Petersburg and Manheim would be needed to keep PA 72 from becoming choked with traffic.  However, there is a snag in the funding for this project.  PennDOT released their revised 12-Year Transportation Program in 2004 and this project was deferred.

Signed in 1928 on the current alignment, and the route was paved from the New Hanover Township line to Layfield.  In 1929, the route was under construction  from Schwenkville to PA 113 and completed the following year when the route was paved from PA 23 to Knauers.

In 1931, the route was under construction from Boyertown to Gilbertsville and completed the following year.  In 1954, the route was moved to Perkiomen Avenue for eastbound traffic in Reading.

In 1962, the western terminus was moved from PA 23 in Goodville to Mount Penn.  In 1964, the western terminus was moved from US 422 in Mount Penn to its current location.  In 1968, the route was moved from Frankford Avenue, Robins Avenue (eastbound), and Levick Street (westbound) to its current alignment between US 13 and the Tacony-Palmyra Bridge.

In 1930, the route was paved from Ickelsburg to Marshrun and Donnally Mills to Millerstown.  In 1932, the route was paved from Marshrun to Donnally Mills.  In 1938, the section from PA 944 to Lebo opened, while the same time the sections between Lebo and Bridgeport, and PA 274 to PA 894 were paved.

In 1941, the northern terminus was moved from Carlisle to Ickesburg.  In 1947, the section at the Cumberland and Perry County line was paved.

In 1950, the route between Icklesburg and PA 75 was finished.  Paved from Perry County line to PA 75 in 1953.  In 1951, the route was split from Market Street with Philadelphia Street taking northbound traffic with southbound remaining on Market in York.

Northern terminus was moved from PA 17 in Ickesburg to its current location in 1965.  In 1989, a median was installed on the section at the US 30 interchange in York.

The route was closed August 8, 2009 between the Maryland state line and PA 851 due to delivery of a large transformer to the Peach Bottom Atomic Power Station in Delta.

In 1928, the route was under construction from Fort Loudon to Richmond Furnace and completed the following year.

In 1930, the route was paved from Seven Pines to Turbett.  In 1932, the route was paved from Honey Mills to Seven Pines.  In 1936, the section between Blairs Mill and Waterloo was improved.  In that year the southern terminus was moved from Fort Loudon to the Maryland state line.  In 1938, the section from Berry Ridge Road to East Waterford was paved.

In 1940, the section from the Huntingdon County line to Berry Ridge Road was paved.

In 1930, the section from Cassville to Calvin was paved.  In 1932, the northern terminus was moved from Mill Creek to Reedsville.  Also that year, the highway was paved form Harrisonville to Waterfall, from Saltillo to Knightsville, and from Morgans Road to Mill Creek.  In 1935, the sections from Tonoloway Creek to Harrisonville and Waterfall to Saltillo were paved.  In 1936, the section from South Gordon Lane to Sam's Road was paved.  In 1938, the sections between Colvalt Road and South Gordon Lane and from PA 376 to Cassville were improved.

In 1940, the section between Fisher Road and Needmore was improved while the section between PA 376 and Cassville was paved.  In 1947, the route was paved from Johnsons Mill Road to Colvalt Road.

SR 0076 is currently assigned to Interstate 76.

In 1932, the section from PA 277 to Garland was paved.  In 1934, the section from PA 408 to Little Cooley was under construction and opened the following year.  Also the section from Spring Creek to Eldred Hill Road was paved.

In 1936, the section from Downey Ferry Road to Riceville Road was paved and so was the section from Eldred Hill Road to Chapman Road.  In 1938, the section from Chapman Road to Garland was paved.  In 1941, the section in Garland was paved.

In 1961, the western terminus was moved from Park Avenue to its current location.

In 1977, the eastern terminus was changed from PA 27 in Garland to the current location.  Previous to that, the route traveled to Spring Creek and then followed the current PA 426 alignment to Garland.

In 1930, the route was paved from the Wolf Creek Township line to Sandy Lake and Deckards Run Road to Lake Creek Road.  In 1936, the northern terminus was moved to PA 408 from PA 27. and the southern terminus was moved from Grove City to Slippery Rock.

In 1941, the southern terminus was moved from Slippery Rock to Stone House.  The section from PA 198 to PA 408 was paved in 1946.

SR 0078 is currently assigned to Interstate 78.

Originally, the western terminus was at US 20 in West Springfield and the eastern terminus at US 6 in Elgin.  However, in 1936, the route was truncated to make way for US 6N's new alignment.  And the eastern terminus was cut back from Spartansburg to Concord Corners.

SR 0079 is currently assigned to Interstate 79.

In 1952, the designation was moved off the current PA 380 alignment from PA 286 to Wilkinsburg onto the US 22 alignment and onto the Penn-Lincoln Parkway.  In 1959, the western terminus was moved from the Boulevard of the Allies to the Fort Pitt Bridge.

SR 0080 is currently assigned to Interstate 80.

Technically not a continuous route since 1972 when Hurricane Agnes washed away several bridges over Hay Creek just south of Birdsboro.  PennDOT has never, and will never replace the destroyed spans due to local opposition.  This was the reason that the route was truncated in Elverson in December 2008.  The remainder of the route to Birdsboro became SR 4082 in Chester County, SR 2082 in Berks County, and PA 345 north to US 422.

In 1932, the route was under construction from Rehersburg to US 22 and paved from US 22 to PA 443.  In 1946, a bypass of Rehrersburg opened to the east of town.  In 1960, the route was moved from New Schaefferstown Road and Four Point Road to a more straight route between the two.

SR 0083 is currently assigned to Interstate 83.

In 1930, the route was paved from Joe's Run Road to the Cummings Township line and Sweetbriar to Wellsboro.  In 1932, the section from the Mifflin Township line to Sweetbriar.  In 1941, the northern terminus was moved to PA 549 from Tioga.

SR 0084 is currently assigned to Interstate 84.

In 1940, the section from the Crawford County line to US 6N was improved.  In 1947, the section from PA 198 to Cambridge Springs was paved.

In 1951, the section from the Crawford County line to US 6N was paved.  In 1953, the section from Cambridge Springs to the Erie County line was paved.

In 1983, the northern terminus was moved from US 19 four miles north of Waterford via Old State Highway 86 Road, Conneauttee Valley Road, and Sharp Road to its current location.

Even though this is signed as PA 86, it does not have the SR 0086 designation.  That was moved to Interstate 86 when it was signed in 1999.

In 1930, the route was paved from West Brownsville to California.  The designation was moved onto Library Road from Bethel Park to PA 51.  The designation had been signed on Baptist Road to end at PA 51 in Brentwood prior to the construction of Saw Mill Run Boulevard.  In 1935, the northern terminus was moved from PA 51 to Rochester and a year later to New Castle.

In 1952, the West End Bypass opened to traffic from the Penn-Lincoln Parkway to PA 837.  A median was installed in 1958 between Freedom and Baden, Ambridge to Edgeworth, and Glenfield to Emsworth. 

A median was installed in 1960 between Baden and Ambridge.  A year later, the northern terminus was moved from New Castle to its current location.

In 1975, construction began on the section of expressway from Low Hill Road to US 40.  This section opened in 1977.

In 1983, the designation was moved onto the expressway section from Low Hill Road to US 40, and then multiplexed with US 40 to the exit with its original route.  In 1984, when the newest section of the Mon-Fayette Expressway opened between Exit 32 and Exit 34, the designation was moved onto it from its route hugging the cliff along the Monongahela River.  It was moved back to the original route in 1991.

If you drive though the intersection at PA 51 and Maytide Street can be a nasty bottleneck.  However, PennDOT is exploring making changes at that intersection.  The varying plans call for building an interchange all the way to keeping the at-grade intersection but improving it with jughandles to eliminate left turns.

After nearly 80 years of service, the Point Marion Bridge, or Albert Gallatin Memorial Bridge, that carried PA 88 over the Monongahela River, was deemed unsafe and construction on a replacement began on January 7, 2008.  The new $21 million crossing opened on October 22, 2009, and the original was imploded on November 16, 2009.

A sinkhole caused by mine subsidence led to closure of the route in Allenport on August 6, 2009.  The hole was estimated at 12 feet wide and 20 feet deep and repairs took three weeks to complete.

In 1932, the section from Concord Corners to Ovid was paved.  In 1936, the section from Beaverdam to Ladd Road was paved.  That year the southern terminus was moved from Elgin to Titusville.

The route was paved from Concord Corners to Darrows Corners in 1938 and so was the section from Ladd Road to Wattsburg. In 1940, The section from the Rome Township line to East Brach of Oil Creek was paved.

In 1941, the section from the East Brach of Oil Creek to PA 77 was paved.  In 1953, the northern terminus was moved to its current location from US 20 in North East.

In 1932, the route was paved from Stroudsburg to Analomink, Cresco to Haags Mills and Dyberry to Equinunk.  In 1934, the section from just north of Stockport to the New York state line was under construction and opened the following year.  In 1938, the section from Monroe County line to Ledgedale Road was paved, while the section from there to Hamlin was improved.  Also the section from just north of Stockport to town was paved.

In 1940, the section from Ledgedale Road to Hamlin was paved and Hoadleys to Terrace Street in Honesdale was improved.  In 1941, the southern terminus was moved from US 611 in Stroudsburg to US 22 in Easton via the current PA 191 alignment to Stockertown and Sullivan Trail to Easton.  Also the section from Equinunk to Stockport was paved.  In 1946, the section from Hoadleys to Terrace Street in Honesdale was paved

PA 90 was to be revived for the cancelled Pulaski Expressway in Philadelphia.  SR 0090 is currently assigned to Interstate 90.

In 1932, the route was paved from the Luzerne County line to Tunkhannock and from Lenox to Gelatt.  In 1934, the sections from Nicholson to Lenox and Gelatt to Susquehanna were under construction and opened the following year.

In 1940, the section from the Luzerne County line to Bowman Creek was paved.  In 1946, it swapped alignments with PA 309 between West Pittston and Bowman Creek.  Prior to that the route started in Kingston at US 11.

In 1946, the eastern terminus was moved from Buffalo Creek Road at PA 45 east of Mifflinburg to Lewisburg.

SR 0095 is currently assigned to Interstate 95.

In 1936, the section form Willis Creek to Shirey Road was paved.  In 1938, the section from Hyndman to Willis Creek was paved.  In 1973, the northern terminus was moved from Pleasantville to its current location.

In 1928, the route was under construction from Town Hall Road Kearsarge and completed the following year.  In 1930, the section from Sharp Road to Town Hall Road was paved.  In 1935, the section from Waterford to Sharp Road was paved.

Signed on its current alignment in 1936.

Until 1955, the southern terminus was in Meadville.  That year it was moved to its current location.

In 1936, it was signed on its current alignment.  In 1952, construction started on a new alignment north of Middleboro and finished in 1953.  In 1962, the northern terminus was moved from US 20 in Erie to its current location, eliminating the multiplex into Erie from Millcreek.  In 1971, the route was widened and a median installed from near Interstate 79 to US 19.

It was the last state route in Pennsylvania to share an SR designation with another route.  The SR 0099 designation is now solely used to designate Interstate 99 when its final section opened between Bald Eagle and State College in 2008.

In 1956, the Pottstown bypass opened from south of the city to old US 422.  In 1958, the route was widened and a median installed from Pottstown Pike in West Chester to Exton.  In 1958, the designation was moved back to the old route, and the following year the segment from West High Street to north of the city opened.

In 1964, a median was installed from Pottstown to New Berlinsville, and moved back out of Pottstown.

In 1970, what would become a future part of the route opened to traffic.  That section being the expressway segment from US 202 to Pottstown Pike in West Chester.  In 1971, the route was widened and a median installed from Exton to Lionville.  The following year the same was performed from south of Pottstown to West High Street.

In 1989, the route was widened and a median installed from Lionville to the Pennsylvania Turnpike interchange.

Construction began on Phase One of the Trexlertown Bypass on April 26, 2002 which involved earth moving and placement of more than one million cubic yards of earthen fill at the interchange area near Breinigsville and a replacement wetland area near Trexlertown Road and Spring Creek Road.  The advance contract was necessary to allow the embankments time to settle and compress the clay layers beneath the interchange.  This phase was completed in late 2002 at a cost of $6.8 million.

On April 4, 2003 construction began on Phase Two of the bypass which begins south of Spring Creek Road and ends north of Ruppsville Road.  The new $46.5 million highway opened on September 27, 2005 and the designation removed from Trexlertown Road.

In 2003, the southern terminus was moved from the Delaware state line one-half mile south of Cossart to US 202.  The move came at the request of West Chester residents who complained about the amount of traffic going through the borough.

On June 16, 2005, PennDOT announced work would begin on a $13.6 million project to install ITS equipment on PA 100 in Chester County.  Over the next 15 months, crews installed 33 closed circuit TV cameras, 22 dynamic, and 61 incident detectors along the route as well as US 30 in Chester County and US 202 in Delaware and Chester Counties.  They are connected to the Philadelphia Traffic Control Center in King of Prussia.