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 long 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 this section of I-99 was $702 million. This left the work on the planned high speed interchange joining I-80 and I-99. 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 freeway leading U.S. 15 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. Overall costs to build Interstate 99 in New York were $238 million.11