Interstate 99 is a rural freeway traveling northward through central Pennsylvania from Bedford near the PA Turnpike (I- 70/76) to I-80 near Bellefonte. Also known as the Appalachian Thruway and the Bud Shuster Byway, it is the first Interstate highway to have its designation written into law (National Highway Designation Act of 1995). The designations for several other Interstates, including I-66 in Kentucky, I-86 in New York, and I-69 in Texas, were subsequently written into law.
Ultimately, I-99 will continue north from I-80 via U.S. 220 to Lock Haven and Williamsport, and along U.S. 15 north to the New York state line by Lawrenceville. The short section of U.S. 15 leading north to I-86 at Painted Post, NY was designated as Interstate 99 on June 27, 2014.1
Speed limits along Interstate 99 were raised to 70 miles per hour (mph) from mile marker 34 in Blair County to Exit 68 in Centre County, and from mile marker zero at the PA Turnpike in Bedford County to Exit 28 in Blair County. Additionally a 49 mile stretch of U.S. 15, from PA 14 in Lycoming County to the New York state line, was increased to 70 mph. PennDOT announced increases on these stretches in May 2016.2
Located east of I-79 and west of I-81, I-99 falls outside the standard numbering convention outlined for Interstate highways. Under the orderly system, odd numbered Interstates increase in number from I-5 on the West Coast eastward to the Atlantic seaboard. While central Pennsylvania is pretty far east, it is still well away from the Atlantic Ocean. Several north-south routes, including I-81, I-83, I-87, I-89, I-91, I-93, I-95 and I-97 all lie east of Interstate 99. Congressman Bud Shuster both determined the number for the Appalachian Thruway and was responsible for writing Interstate 99’s designation into the 1995 National Highway Designation Act.
Interstate 80/99 Interchange
A $35 million Infrastructure for Rebuilding America Grant (INFRA) was awarded to the Pennsylvania Department of Transportation toward funding construction of a high speed interchange linking I-99 with I-80 near Bellefonte on June 5, 2018. Estimated to cost around $200 million,14 the new ramp system will replace the parclo A2 interchange at U.S. 220 and PA 26 presently joining the north end of I-99 with Interstate 80.
The overall project consists of three sections. Initial construction will add a new local access interchange connecting I-80 with PA 26. PennDOT will open bids for the diamond interchange in April 2020. Completion there is anticipated for December 2021. The remainder of work building the three-wye interchange for I-80/99 will go out to bid in March 2022. Construction includes the realignment and expansion of PA 26 along Jacksonville Road. Work runs through December 2025.14
High Priority Corridor
Interstate 99 in central Pennsylvania is part of High Priority Corridor 9: Appalachian Thruway Corridor.
Parallel U.S. Routes
Interstate 99 between Bedford and Bellefonte overlaps with U.S. 220 for its entirety, and it will continue along U.S. 220 until reaching U.S. 15 at Williamsport. Interstate 99 is currently cosigned with U.S. 15 in New York, and will overlap or replace U.S. 15 southward to Williamsport when it is finally signed.
The southern terminus of Interstate 99 in Bedford may change in the future, as the highway is part of the Appalachian Thruway/High Priority Corridor 9. Improvements are envisioned for U.S. 220 south to Cumberland, though expansion to Interstate standards are not presently planned.
It is also possible that Interstate 99 could continue north all the way to Rochester via I-390. Although some discussions have considered the possibility of I-83 continuing north to Rochester, it does not appear that will occur due to the large gap of Interstate-standard freeway between Harrisburg and U.S. 15.
The initial section of the U.S. 220 freeway opened south from Bedford Township to U.S. 30 in 1969. The remainder of the route north through Bedford and Blair Counties was built in the 1970s and 1980s.3 $138 million in upgrades to Interstate standards took place along the U.S. 220 freeway north from Bedford to Bald Eagle to 1989.4 Discussions followed in the early 1990s to extend the freeway north 30 miles through Centre County to I-80 near Bellefonte.3 Spearheaded by U.S. Rep. Bud Shuster, R-Everett, the first signs for I-99 were unveiled on December 1, 1995 near the interchange with 17th Street in Altoona. The designation of 35 miles of U.S. 220 between Bedford and Altoona was included in the National Highway System Designation Act signed by President Clinton on November 28, 1995. The bill added 161,000 miles of roads into the National Highway System, which gained priority for federal funding. The law provided $118 million of the estimated $370 million needed at the time to complete the 30-mile I-99 corridor north from Bald Eagle through State College.4
Three sections were proposed in 1995 to complete Interstate 99 north from Bald Eagle to the Bellefonte Bypass (Pennsylvania 26). The 17.5 mile segment from Bald Eagle to U.S. 322, including a bypass of Port Matilda, was estimated to cost $365 million. This section stretches across Skytop Mountain to join the Mount Nitanny Expressway (U.S. 322 around State College).4
The second section involved upgrading U.S. 322 between Scotia Road and Park Avenue Extension, and a relocation of PA 26. Also included was a new eight mile alignment linking U.S. 322 at Park Avenue Extension with the Bellefonte Bypass. Expansion of the four-mile Bellefonte Bypass in Spring Township represented the last section at a cost of $180 million.4
An Environmental Impact Statement for I-99 over Bald Eagle Ridge was completed by PennDOT in 1996. The approval of TEA-21 by Congress in 1998 included a two-sentence rider by U.S. Rep. Bud Shuster that eliminated federal oversight of Interstate 99.3 Subsequent approval for Interstate 99 between Bedford and Bald Eagle was approved by AASHTO”s Route Numbering Subcommittee on November 6, 1998.
Land clearing for I-99 commenced in 1999 near Bellefonte and a $39 million contract to build 1.3 miles of new roadway over Bald Eagle Ridge at Skytop was awarded in 2001.3 Meanwhile the eight mile link between State College and Interstate 80 opened to motorists on November 25, 2002. Costing $200 million to build, the segment includes six interchanges.5
North End – Painted Post, NY
South End – Bedford, PA
Branch Routes – 0
Total Mileage – 98.34
Pennsylvania – 85.74
Cities – Bedford, Altoona, Bald Eagle, State College, Bellefonte
New York – 12.60
Cities – Corning
- Junctions –
Source: December 31, 2018 Interstate Route Log and Finders List
I-99 Annual Average Daily Traffic (AADT)
Interstate 99 debuted on the 1995 Official Pennsylvania Highway map from the trumpet interchange with the U.S. 220 Business access road in Bedford to PA 350 at Bald Eagle.
Construction of the route west of State College, known as the “Skytop” section, was hampered with delays due to environmental concerns associated with acid rock–sandstone laced with pyrite. Without measures in place to prevent contamination of streams and ground water, crews in 2003 unearthed a million cubic years of the pyrite-laced sandstone, which when exposed to air and water creates sulfuric acid. $82.7 million in work ensued in 2004 to contain the runoff and clean up the site. This delayed work from an anticipated 2006 completion date.3
Following years of delays, the 14-mile link between Bald Eagle and Patton Township opened on December 17, 2007, with the exception of the 1.4-mile section at the acid-rock drainage cleanup site on Skytop Mountain.6
The section between Skytop and State College was finally completed on November 17, 2008, when eight miles of the freeway southbound opened. Total costs for I-99 totaled $702 million. This left the work on the planned high speed interchange joining Interstates 80 and 90. Projected to cost $146 million in 2008, redesign of the exchange was undertaken to avoid excavating too much pyrite.3
The remainder of Interstate 99 in Pennsylvania is a future route with signs proclaiming its extension along U.S. 220 to Lock Haven and Williamsport, then northward along U.S. 15 to the state line at Lawrenceville.
Several decades of construction upgraded U.S. 15 between Williamsport and Painted Post to limited access standards. A new freeway for U.S. 15, from Tioga, Pennsylvania north to Lindley, New York, opened after a ribbon cutting ceremony held on October 1, 2008. The seven mile segment cost $118.7 million.7 See photos of the roadway on John Walter’s site.
Interstate 99 in New York
Within Steuben County and the village of Painted Posted, New York, construction to upgrade the exchange between the Southern Tier Expressway and U.S. 15 (Interstate 99) started in November 2003. The first phase of work involved a $41 million project to bring U.S. 15 up to Interstate standards and to add a diamond interchange with NY 417 (Addison Road / Hamilton Street). The second phase, costing $11 million, rebuilt a two-mile stretch of I-86 by the north end of U.S. 15.8
The final phase of the Painted Post Interchange project added flyovers for the eventual U.S. 15 freeway leading south to Presho and reconstructed Hamilton Street and Robert Dann Drive. The $70 million project commenced in spring 2005 and was scheduled for a fall 2007 completion.9 Delays pushed work to a ribbon cutting ceremony held on the morning of August 13, 2008. Total costs for the three-phase project topped out at $141 million.10
Road construction on the final five mile portion, north from Watson Creek Road at Lindley to Presho, began in August 2012. Taking place as $46 million in ground work wrapped up, the $31 million project included building six bridges.8 Completion took place on October 8, 2013. Total costs to build Interstate 99 in New York were $238 million.11
North End – NY Section – – Painted Post, New York
Interstate 99/U.S. 15 overlap south by Presho and Lindley to the Pennsylvania state line. U.S. 15 extends south from there as a freeway to Mansfield and I-180 at Williamsport. NY 417 is the pre-freeway alignment of NY 17 between Olean and Gang Mills in southern Allegany and Steuben Counties. 01/18/17
North End Throwback
North End – PA Section – – near Bellefonte, Pennsylvania
I-99/U.S. 220 travel from the Mount Nittany Expressway (U.S. 322) at State College to Interstate 80 northeast of Bellefonte. The freeway transitions into an at-grade expressway at Musser Lane, 0.4 miles ahead of the eastbound on-ramp for I-80. These overheads were replaced by 2015 and the concrete roadway was covered with asphalt. 04/30/05
Historic Northern Terminus – – Bald Eagle, Pennsylvania
An end shield preceded a wye interchange taking U.S. 220 back onto its old alignment from I-99 at Bald Eagle. Photo taken by Oscar Voss (07/99).
PA 350 (7 Stars Road) westbound combined with U.S. 220 at a T-intersection just north of the temporary freeway end of I-99. Photo taken by Tim Reichard (04/07/02).
PA 350 combined with U.S. 220 north to U.S. 220 Business (Eagle Valley Road) at nearby Bad Eagle while U.S. 220 south combined with I-99 to Tyrone and Altoona. The temporary freeway end is now an access road linking Bald Eagle with I-99 via a diamond interchange (Exit 52). Photo taken by Tim Reichard (04/07/02).
South End – Bedford Township, Pennsylvania
An end shield for I-99 stands ahead of the trumpet interchange (Exit 1) with the access road linking U.S. 220 with U.S. 220 Business. The U.S. 220 freeway extends another three miles to Bedford. The US highway reaches the Maryland State line in 27 miles. Photo taken by Oscar Voss (07/99).
Exit 146 departs following the Bugle Road and U.S. 220 freeway overpasses for U.S. 220 Business. U.S. 220 Business leads motorists north 0.3 miles to an access road linking with I-99 north to Altoona and U.S. 220 south to Cumberland, Maryland. A similar surface route connection links the PA Turnpike with I-81 at Carlisle. Photo taken by Chris and Amber Lokken (06/24/08).
South End Throwback
- “Steuben County stretch of Route 15 designated as Interstate 99.” The Leader (Corning, NY), June 27, 2014.
- “Infrastructure – Speed limit extension announced.” Wayne Independent, The (Honesdale, PA) May 7, 2016.
- “Long-awaited Interstate 99 Finished – Road was Long, Rocky and with Stops for Direction.” Centre Daily Times (State College, PA), November 23, 2008.
- “Map Makers Must Draw in New I-99.” Centre Daily Times (State College, PA), December 1, 1995.
- “Drivers Hit Onramps of New I-99.” Centre Daily Times (State College, PA), November 26, 2002.
- “I-99 Link Opens – Connection to Skytop Complete after Years of Setbacks.” Centre Daily Times (State College, PA), December 18, 2007.
- “Work complete on U.S. 15 section.” Leader, The (Corning, NY), October 2, 2008.
- “Final phase of U.S. 15 upgrade underway – I-99 Conversion.” Leader, The (Corning, NY), August 21, 2012.
- “I-86, Rt. 15 interchange under way.” Leader, The (Corning, NY), January 7, 2004.
- “Interchange project prepares for final phase.” Leader, The (Corning, NY), October 22, 2004.
- “Interchange complete.” Leader, The (Corning, NY), August 14, 2008.
- “Route 15 open for business 10-year future I-99 project hits finish line in Lindley – 10-year future I-99 project hits finish line in Lindley.” Leader, The (Corning, NY), October 9, 2013.
- Interstate 86 / Route 15 Interchange Website – Project History,
- “PennDOT Details New Local Access Tied to I-80/I-99 Interchange Project.” Centre County Gazette (State College, PA), March 1, 2019.
Page updated January 21, 2020.