Interstate 99
Interstate 99 (I-99) is a north–south Interstate Highway spanning 85.75 miles through central Pennsylvania from an interchange with the Pennsylvania Turnpike (Interstate 70/Interstate 76) near Bedford to a junction with Interstate 80 near Bellefonte.[1] The route largely overlays and upgrades sections of U.S. Route 220, providing a limited-access freeway through rural and semi-urban areas including Blair and Centre counties, facilitating travel between the Altoona region and the State College vicinity without at-grade intersections.[2] A separate, disconnected 12.89-mile segment of I-99 exists in southern New York, where it follows U.S. Route 15 from the Pennsylvania state line to Interstate 86 near Corning.[3] Designated as an Interstate in federal legislation during the late 1990s amid efforts to improve regional connectivity, the Pennsylvania portion's signage was officially implemented on December 10, 2008, following upgrades to meet federal standards that began in the early 1990s.[4] Construction costs exceeded expectations due to challenging terrain in the Appalachian ridges, with full opening to traffic occurring progressively through the 2000s. The highway's numbering deviates from the standard Interstate grid system, lacking a parent route like Interstate 9, a choice attributed to political influence from former U.S. Representative Bud Shuster, whose district benefited from earmarked federal funding for the project.[5] Notable challenges during development included geological issues at the Skytop section near State College, where excavation exposed pyritic rock, generating acidic runoff that contaminated local waterways and required extensive remediation efforts by PennDOT.[6] Critics, including fiscal watchdogs, have highlighted the route as an example of congressional pork-barrel spending, with disproportionate federal investment for limited traffic volume compared to national averages.[5] Recent initiatives seek to extend I-99 designation northward along U.S. Route 15 in Pennsylvania to connect the segments, potentially enhancing freight and commuter links to the Southern Tier of New York.[7]Route description
Southern segment
The southern segment of Interstate 99 begins at milepost 0 in Bedford Township, Bedford County, Pennsylvania, at a trumpet interchange with the Pennsylvania Turnpike (Interstate 70 and Interstate 76, Exit 146), where the freeway continues southward as U.S. Route 220 toward Bedford.[8] [9] Concurrent with U.S. Route 220 throughout, the four-lane divided freeway heads north through rural, rolling Appalachian terrain, initially paralleling the Raystown Branch of the Juniata River.[8] The first interchange at mile 3 provides access to Pennsylvania Route 56 east toward Cessna and the Bedford County Airport, as well as U.S. 220 Business west.[9] Crossing into Blair County near mile 7, the route serves access to Pennsylvania Route 869 toward Saint Clairsville and Osterburg, followed at mile 10 by an exit for Blue Knob State Park via local roads to Imler.[9] By mile 15, an interchange connects to U.S. 220 Business for Claysburg and the Juniata River communities of King and Sproul.[9] The freeway then approaches the Altoona metropolitan area from the east, bypassing Hollidaysburg; Exit 23 at mile 23 links to U.S. Route 22, Pennsylvania Route 36, and Pennsylvania Route 164 toward Roaring Spring, Portage, and the Altoona-Blair County Airport.[8] [9] Further access to the region includes Exit 28 to U.S. 22 and Pennsylvania Route 764 west for Duncansville and the Horseshoe Curve, Exit 31 to U.S. 220 Business and Plank Road (serving the Blair County Convention Center), Exit 32 to Pennsylvania Route 36 via Frankstown Road and Canoe Creek State Park, and Exit 33 to 17th Street into Altoona's central business district.[9] North of Altoona, the route traverses Logan Valley, with Exit 39 at mile 39 to Pennsylvania Route 764 south toward Pinecroft and a park-and-ride lot, Exit 41 to Pennsylvania Route 865 north for Bellwood and DelGrosso's Amusement Park, and Exit 45 for Tipton and Grazierville near the Horseshoe Curve overlook.[9] Approaching Bald Eagle Valley near Tyrone, Exit 48 connects to Pennsylvania Route 453 north to Tyrone and south to Huntingdon.[9] The segment concludes at Exit 52 with Pennsylvania Route 350 and U.S. 220 Business to Bald Eagle, marking the Blair-Centre county line and the ascent toward Bald Eagle Mountain.[9] [8] This portion, completed in phases through the 1990s, provides a signal-free corridor through forested ridges and small communities, facilitating regional travel while avoiding urban congestion in Altoona.[4]Northern segment
The northern segment of Interstate 99 comprises a 12.89-mile (20.75 km) freeway entirely within Steuben County, New York, running concurrently with U.S. Route 15 from the Pennsylvania state line northward to a trumpet interchange with Interstate 86 and New York Route 17 (the Southern Tier Expressway) at exit 44 in Painted Post.[3][10] This portion, the only signed section of I-99 in New York, utilizes a milepost-based exit numbering system, the first such implementation in the state, with mile 0 at the southern border.[3] The route begins as a continuation of the US 15 freeway from Pennsylvania, entering New York adjacent to Lawrenceville in Tioga County, Pennsylvania, and immediately traversing rural, hilly terrain through the town of Lindley.[11] It features a rock cut and a pronounced northward curve, bypassing local hamlets, with the first interchange at approximately mile 1.6 for County Route 119 serving Lindley.[10] Continuing north across the Cohocton River into the town of Erwin, I-99/US 15 reaches an interchange with NY 352 (Victor Hugo Parkway) at mile 8.5 near Gang Mills, providing access to Corning.[10] The segment maintains four divided lanes throughout, designed for higher speeds in the Southern Tier region, before terminating at the I-86/NY 17 junction, where northbound traffic can connect west to Erie or east toward Binghamton.[3][10] Long-term plans envision extending I-99 southward through Pennsylvania along US 220 and US 15 to connect with the Pennsylvania segment near Bellefonte, though no construction has advanced beyond planning as of 2025.[2]Gaps and interim connections
The southern terminus of the designated Interstate 99 corridor in Pennsylvania ends at an interchange with PA 26 and PA 550 near Port Matilda in Halfmoon Township, Centre County, approximately 3 miles (4.8 km) south of Interstate 80.[4] Northbound traffic seeking to continue toward the northern segment must transition to surface routes, primarily US 220, which serves as the interim connection spanning roughly 70 miles (110 km) to Williamsport in Lycoming County, where the northern Interstate 99 segment begins concurrent with US 15 at the I-180 interchange.[12] [2] Within this US 220 corridor, two principal gaps persist where the route lacks continuous limited-access freeway standards: from near Interstate 80 in Clinton County to Salona, and from Jersey Shore to Williamsport.[12] These segments include at-grade intersections, traffic signals, and substandard alignments, contrasting with the interstate-grade portions south of the gaps. Environmental and planning studies for upgrades began around 2000 but were deferred in 2004 due to funding and prioritization issues.[4] Interim travel relies on the existing US 220 alignment, which features intermittent divided highway sections—such as the freeway bypass around Lock Haven—but reverts to two-lane or partially controlled access roads in the gaps, contributing to higher accident rates and travel times averaging 1.5 hours for the full interim span under typical conditions.[12] Long-term proposals envision upgrading these gaps to Interstate 99 standards to create a continuous route from Bedford to the New York state line, though no construction contracts have been awarded as of 2024.[2] Additionally, the northern end of the southern segment lacks a direct high-speed interchange with Interstate 80; northbound Interstate 99 traffic exits to PA 26 west, navigating a signalized intersection at Ungers Street before accessing Interstate 80 at Exit 158 (Shingletown Road).[13] This interim linkage, in place since the segment's completion in 2008, will be replaced by a $259 million high-speed ramp project connecting Interstate 99 directly to Interstate 80, with construction phases beginning September 2024 and substantial completion targeted for 2030.[14] [15]History
Origins in US 220 corridor improvements
The upgrades to the U.S. Route 220 (US 220) corridor in Pennsylvania originated in the post-World War II era, driven by rising traffic demands and the need for safer, higher-capacity roadways connecting southern Pennsylvania to the northern tier and beyond. Initial efforts focused on widening the two-lane highway to four lanes in select areas; in 1951, widening was completed in Bedford and from Palmers Lake to Williamsport.[12] By 1956, the interchange with the Pennsylvania Turnpike in Bedford was expanded, followed in 1958 by widening from Montoursville to Halls and Towanda, along with median installations in segments near Hollidaysburg, Lakemont, Greenwood, and Antis Township.[12] These projects addressed immediate congestion and accident risks but fell short of full freeway standards, as US 220 remained largely at-grade with signalized intersections. The 1960s marked a transition to expressway development, aligning with broader national trends toward limited-access highways under the Interstate era's influence, though US 220 was not initially part of the core Interstate system. Construction began in 1967 on key segments, including the expressway from Avis to Jersey Shore and the at-grade portion from Milesburg to Blanchard.[12] Openings followed in 1969, with freeway sections from Milesburg to PA 26, Avis to Thomas Street, and along I-80 between exits 158 and 161 becoming operational.[12] Medians were added in areas like PA 36 to South 22nd Street, enhancing divided highway characteristics and reducing head-on collisions, though gaps persisted due to challenging terrain in central Pennsylvania counties such as Centre and Blair.[12] Momentum accelerated in the 1970s with bypass constructions to circumvent urban bottlenecks and mountainous obstacles. The Bedford Bypass opened in 1970, linking Business US 220 to PA 56 and diverting through traffic from downtown.[12] The Tyrone Bypass followed in 1976, alongside the Towanda Bypass, while the Bellefonte Bypass—a "Super-2" expressway with passing lanes—began construction in 1971.[12] Additional expressway openings in 1974 connected Maynard Street to Hepburn Street and Pine Street to the Southern Tier Expressway, and by 1978, US 220 was realigned onto new freeway alignments from Milesburg to Avis and integrated with I-80 segments.[12] These developments, funded primarily through state and federal aid highway programs, converted approximately 50 miles of the corridor south of State College into divided freeway by decade's end, improving freight movement and regional access but leaving northern extensions incomplete.[2] The 1980s consolidated these gains by filling remaining gaps and elevating standards toward Interstate compliance. A major 1980 opening spanned PA 56 to King/Claysburg, while 1986 brought relief to Altoona via the Newry Lane to 17th Street segment.[12] Further completions in 1988–1989 linked PA 164 to Newry Lane and King/Claysburg to PA 164, with gaps around Tipton and Grazierville closed between 1991 and 1995.[12] By 1989, investments exceeding $138 million had upgraded the route from Bedford northward to Bald Eagle, establishing a continuous freeway corridor that prioritized safety through full interchanges, grade separations, and modern pavements.[2] These phased improvements, spanning over three decades, transformed US 220 from a rural arterial into a high-speed spine for central Pennsylvania, facilitating economic ties to ports in Baltimore and Hampton Roads while preempting its later Interstate 99 designation.[16]Designation process and Bald Eagle Valley bypass
The designation of Interstate 99 originated with the National Highway System Designation Act of 1995, signed into law on November 28, 1995, which explicitly designated a 65-mile segment of U.S. Route 220 in central Pennsylvania—from its junction with the Pennsylvania Turnpike (Interstate 70/76) near Bedford northward to Interstate 80 near Bellefonte—as Interstate Route 99.[17] This congressional mandate bypassed the customary process where the Federal Highway Administration (FHWA) and American Association of State Highway and Transportation Officials (AASHTO) assign route numbers based on geographic and sequential conventions, marking the first time Congress directly specified an Interstate designation in statute.[2] U.S. Representative Bud Shuster (R-PA), chairman of the House Committee on Transportation and Infrastructure from 1995 to 2001, advocated for the provision after securing earmarks for U.S. 220 upgrades through the Appalachian Development Highway System and Interstate Cost-Sharing programs, aiming to accelerate federal funding for the corridor's conversion to full Interstate standards including divided lanes, controlled access, and 70 mph design speeds.[4] The numbering "99" contravened AASHTO guidelines, which allocate odd numbers to north-south routes but assign them sequentially from west to east (e.g., I-81 lies to the east of the corridor); FHWA approved the non-standard label only after the legislative directive, prioritizing statutory authority over traditional routing logic.[18] Full Interstate signage and official commissioning followed construction milestones, with the route certified and marked as I-99 on December 10, 2008, upon completion of key segments meeting FHWA criteria such as full interchanges and no at-grade intersections.[4] Prior to this, the corridor operated as a mix of upgraded U.S. 220 freeway sections, with funding tied to Shuster's influence over the Transportation Equity Act for the 21st Century (TEA-21) in 1998, which allocated over $200 million for improvements.[2] The Bald Eagle Valley bypass constitutes the northernmost segment of I-99's southern Pennsylvania portion, spanning approximately 14 miles from an interchange with Pennsylvania Route 350 in Bald Eagle northward to Port Matilda in Patton Township, Centre County. Constructed as a four-lane divided freeway to replace the pre-existing two-lane U.S. 220 alignment that wound through Bald Eagle Valley—prone to seasonal flooding, rockslides, and substandard curves—the bypass deviates eastward, traversing Bald Eagle Ridge via cuts and fills to enhance geometric design and sight distances.[2] Groundbreaking for this link occurred amid broader U.S. 220 enhancements funded under TEA-21 and subsequent acts, with major earthwork and bridge construction advancing after 2000 despite environmental reviews for wetland impacts and karst terrain.[4] Opened to bidirectional traffic on December 17, 2007—excluding a 1.4-mile stub near Skytop that connected later—the bypass reduced travel times by over 10 minutes compared to the old valley road and incorporated safety features like rockfall netting on slopes and full-depth paving for 55 mph initial speeds, later raised to 65 mph.[2] This completion bridged a critical gap in the corridor, enabling through traffic from Bedford to I-80 without reverting to local roads, though full I-99 standards extended southward progressively, with the segment's role in freight diversion from U.S. 22 justified by traffic volume data showing 15,000–20,000 annual average daily traffic by 2010.[4] The project cost approximately $150 million, reflecting efficiencies in phased contracting but drawing scrutiny for overruns tied to geological challenges in the ridge crossing.[2]Major construction phases
The freeway corridor underlying Interstate 99 originated with phased construction and upgrades to U.S. Route 220 beginning in the late 1960s, initially as non-Interstate limited-access highways before later meeting full Interstate standards.[4] Early segments included a two-lane "Super 2" freeway from south of Bedford Springs to exit 3, constructed in 1969 and opened in 1970, and extensions through Bedford and Blair Counties built primarily during the 1970s and 1980s.[2] The Tyrone Bypass, spanning exits 45 to 52, followed with construction from 1970 to 1976.[4] Further expansions in Blair County during the 1980s included work from Newry Lane to exit 33, starting in 1982 and extending in 1984 before opening in 1986, alongside segments from exit 15 to Newry Lane completed between 1987 and 1989.[4] The 1990s saw significant upgrades from exit 33 (near Altoona) to exit 45 (Tyrone), initiated in 1991 and opened in 1995, enhancing connectivity ahead of the I-99 designation.[4] By 1989, the corridor from Bedford to Bald Eagle had been upgraded to Interstate standards at a cost of $138 million.[2] A pivotal phase involved the 18-mile Bald Eagle Valley Bypass from Bald Eagle to State College, constructed to avoid the winding pre-existing route through the valley and enable the I-99 designation.[4] Work began in fall 2000, with an original completion target of late 2003, but faced delays due to pyritic rock causing acid mine drainage, adding approximately $100 million in remediation costs.[4] Partial opening occurred on December 17, 2007, for 14 miles to Patton Township, followed by full completion of the Skytop to State College segment (8 miles) on November 17, 2008, at a total cost exceeding $700 million including bridges and interchanges.[2] Earlier related work on the Mount Nittany Expressway to Bellefonte Bypass, started in January 1999, opened on November 25, 2002, for $195 million.[4] These central phases connected the southern upgrades to future northern extensions along upgraded U.S. 220.[2]Engineering and design
Bald Eagle Mountain crossing
The Bald Eagle Mountain crossing on Interstate 99 features a deep rock cut through the mountain's Tuscarora ridge at Skytop, approximately 8 miles northwest of State College, Pennsylvania, enabling a straighter alignment than the winding Bald Eagle Valley route to the east. This 1.4-mile section, completed in phases between 2000 and 2007, involves a 7-kilometer grade ascending the mountain's west slope to an elevation of about 520 meters, with cut depths reaching 40-60 meters in the Ordovician Bald Eagle Formation sandstone.[19][20] The design prioritized higher speeds and reduced curvature for freight traffic, avoiding the valley's flood-prone terrain and sharp turns along legacy US 220. Geotechnical engineering addressed the site's folded and faulted Appalachian strata, incorporating rockfall netting on slopes and drainage systems to manage seepage, though initial assessments underestimated sulfide mineral content. Construction in 2003 exposed pyrite-rich rock beneath a 10-meter gossan cap, generating acid rock drainage (ARD) via oxidation and hydrolysis, which produced sulfuric acid and mobilized zinc, lead, and iron into nearby streams like Halfmoon Creek. Spoil piles, totaling over 1 million cubic yards at sites including Seibert and Skytop, leached at pH levels below 3, prompting Pennsylvania Department of Environmental Protection intervention and halting work in February 2004.[19][21][20] Remediation integrated alkaline addition, such as limestone dosing and magnesium hydroxide slurry trials, alongside capping piles with low-permeability covers and relocating reactive material to lined landfills for neutralization with cement kiln dust. These measures, overseen by PennDOT and costing tens of millions, stabilized drainage by 2007, allowing the section's opening, though monitoring continues for long-term efficacy amid the formation's high sulfur content (up to 5%). Slope stabilization includes wire mesh and shotcrete in high-risk areas to prevent rockfalls, reflecting adaptations from early geological surveys that downplayed ARD risks based on surface pyrite observations near Port Matilda.[20][22] The crossing enhances connectivity between I-80 and US 322 but exemplifies causal challenges in ridge traversals, where overburden removal exposes reactive lithologies absent in valley alignments.[21]Standards and innovations
Interstate 99 adheres to the core design standards of the Interstate Highway System, as codified by the Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO), including a minimum of four 12-foot-wide travel lanes divided by a median, 10-foot outside shoulders and 4-foot inside shoulders, and full control of access through grade-separated interchanges without at-grade intersections.[4] These specifications ensure high-speed travel capacity and safety, with horizontal and vertical alignments designed for design speeds of 70 mph in rural sections, incorporating superelevation and sight distance requirements per AASHTO's A Policy on Geometric Design of Highways and Streets. The Pennsylvania Department of Transportation (PennDOT) applies these federal baselines alongside state-specific criteria from Publication 72M, Design Manual Part 2, which governs elements like pavement cross-sections, drainage, and signage for resilience in Pennsylvania's variable terrain and climate. Innovations in I-99's construction include the integration and monitoring of integral abutment bridges (IABs), which eliminate traditional expansion joints to minimize debris accumulation and corrosion, thereby extending service life in regions with extreme thermal cycling.[23] Pennsylvania State University researchers have utilized I-99 segments to conduct field studies validating IAB performance, focusing on soil-structure interaction and long-term movement under winter freeze-thaw and summer expansion conditions, addressing gaps in predictive modeling for longer spans.[23] This approach represents a shift from jointed designs, potentially reducing lifecycle maintenance by up to 20-30% through simplified construction and fewer leak-prone elements, as evidenced by post-installation instrumentation data.[23] Initial segments, such as the 1972 Bellefonte Bypass, employed a "Super-2" configuration—a two-lane divided expressway built to eventual four-lane freeway standards with partial median separation and limited interchanges—as a cost-effective interim measure before full upgrades to Interstate specifications in the 1990s and 2000s.[4] This phased approach allowed early relief of congestion on US 220 while aligning with evolving FHWA funding eligibility for high-mobility corridors, though it required subsequent widening and barrier retrofits to meet modern crash-test standards like those in AASHTO's Roadside Design Guide.[4]Controversies and debates
Interstate numbering violation
The Interstate Highway System's numbering conventions, established by the American Association of State Highway and Transportation Officials (AASHTO) in coordination with the Federal Highway Administration (FHWA), dictate that north-south routes receive odd numbers, with these numbers increasing sequentially from west to east to facilitate logical geographic orientation.[17] Thus, Interstate 99, as a north-south route bearing a relatively high odd number, would conventionally be positioned east of established routes like I-95 (the easternmost major north-south Interstate at 95) and any hypothetical I-97, potentially along the Atlantic seaboard or further east.[5] However, I-99's actual alignment in central Pennsylvania—extending approximately 13 miles from near Bald Eagle State Forest south to the vicinity of Tyrone, primarily overlapping upgraded sections of U.S. Route 220—places it geographically between I-79 (to the west) and I-81 (to the east), a location warranting a lower odd number in the 70s or low 80s under standard protocols.[24] This discrepancy constitutes a direct violation of the AASHTO grid, as I-99's designation skips ahead in the sequence without regard for its western longitude relative to higher-numbered eastern routes.[5] The FHWA has acknowledged that while AASHTO typically approves Interstate numbers to maintain this system, congressional legislation can override such conventions; in this case, the National Highway System Designation Act of 1995 explicitly mandated the I-99 label for the specified U.S. 220 corridor, bypassing traditional review processes.[17] Critics, including transportation policy analysts, have highlighted this as an anomalous exception driven by non-geographic factors, noting that no other Interstate so flagrantly disrupts the east-west progression of odd numbers, potentially confusing drivers reliant on numeric cues for navigation.[24] The FHWA has not pursued renumbering, citing the binding nature of the statutory designation, though the violation underscores tensions between federal standardization and localized legislative priorities.[17]Political influence and pork-barrel allegations
The designation of Interstate 99, which overlays a segment of the upgraded U.S. Route 220 corridor in central Pennsylvania, was heavily influenced by the efforts of U.S. Representative Bud Shuster (R-PA), who chaired the House Committee on Transportation and Infrastructure from 1995 to 2001. Shuster secured federal funding through the National Highway System Designation Act of 1995 and subsequent transportation authorization bills, including earmarks totaling hundreds of millions for improvements in his district, such as the Bald Eagle Valley bypass completed in phases between 1998 and 2002.[4] In 1998, Congress overrode standard Interstate numbering protocols—typically managed by the Federal Highway Administration and American Association of State Highway and Transportation Officials—by specifying "99" in Section 1105(e)(3) of the Transportation Equity Act for the 21st Century (TEA-21), a move attributed directly to Shuster's legislative leverage to boost prestige and attract further investment for the low-traffic route.[17][5] Critics have labeled the project a prime example of pork-barrel politics, arguing that Shuster funneled disproportionate federal dollars—estimated at over $500 million by the early 2000s for a corridor serving fewer than 10,000 vehicles daily—to benefit rural constituents in Pennsylvania's 9th district, including construction contracts awarded to local firms with ties to his campaign donors.[5] The Cato Institute, a libertarian think tank skeptical of federal spending, dubbed it the "Bud Shuster Highway" and derided it as a "rollercoaster" of unnecessary upgrades leading to a "road to nowhere," citing its violation of sequential numbering (skipping from I-80 to I-99) and minimal national economic justification compared to higher-priority corridors.[5] A 2008 New York Times report highlighted I-99 as "pork barrel spending at its worst," noting that despite traffic volumes below Interstate thresholds (under 8,000 average daily in segments as of 2008), the designation ensured ongoing maintenance subsidies and local job creation, with Shuster expressing no remorse over the federal outlay.[24] Shuster's influence extended through family ties, as his son Bill Shuster (R-PA) succeeded him in Congress and continued advocating for corridor expansions, including extensions toward I-80, amid broader critiques of dynastic earmarking in transportation bills.[25] While proponents, including Pennsylvania officials, defended the investments as essential for regional safety and commerce—pointing to reduced accident rates post-upgrade from 1990s levels of over 100 crashes annually—detractors from fiscal conservative outlets maintained that the project's prioritization reflected congressional logrolling rather than data-driven needs assessments, with TEA-21's $218 billion total authorization enabling such district-specific allocations.[5][24] No formal investigations into corruption ensued, but the episode underscored systemic concerns over committee chairs directing funds to pet projects, a practice curtailed by the 2011 earmark moratorium yet persistent in disguised forms.[5]Environmental and fiscal criticisms
Construction of Interstate 99 encountered significant environmental challenges, particularly during the Skytop section near Port Matilda in Centre County, where excavation in 2003 exposed approximately one million cubic yards of pyritic rock containing iron sulfide minerals.[21] This led to acid rock drainage, producing highly acidic runoff with pH levels below 3 and elevated concentrations of metals such as iron, aluminum, and manganese, which contaminated surface water and groundwater in the Spring Creek watershed.[26][4] The Pennsylvania Department of Transportation's (PennDOT) environmental impact assessment had identified pyrite but underestimated the risk, failing to anticipate the scale of drainage issues, which prompted ongoing remediation efforts including excavation, chemical neutralization, and water treatment.[20][27] Environmental groups, including the Bald Eagle Ridge Protection Association, opposed aspects of the project, arguing it violated federal environmental laws and threatened local ecosystems, though courts largely upheld PennDOT's compliance.[28] The Bald Eagle Valley bypass alignment, which crossed sensitive ridge terrain rather than following the valley floor, drew criticism from environmentalists who favored a less disruptive route to minimize habitat fragmentation and geological risks in the Appalachian ridge-and-valley province. Post-construction monitoring revealed persistent contamination, with groundwater metal levels rising as late as 2007 due to snowmelt and erosion, affecting downstream water supplies used by Pennsylvania State University and nearby communities.[6] Fiscal criticisms centered on the project's escalating costs, driven by political earmarks rather than demonstrated traffic or economic need, with taxpayer watchdog groups labeling it an example of wasteful federal spending.[24][5] The acid drainage remediation alone ballooned from initial estimates to $79 million by 2007, including $30 million in overruns for treatment systems and site stabilization, diverting funds from other infrastructure priorities.[27] Overall corridor upgrades, including I-99 designation and widening, exceeded $700 million for key segments, with critics noting low average daily traffic volumes—around 10,000-15,000 vehicles in early sections—yielding poor cost-benefit ratios compared to maintenance of existing U.S. Route 220.[2][29] These overruns and perceived pork-barrel funding, secured through congressional influence, fueled arguments that the project exemplified inefficient allocation of public resources in a state facing broader transportation funding shortfalls.[30]Economic and regional impacts
Development and job creation benefits
The completion of Interstate 99 has facilitated economic development along its corridor in central Pennsylvania by improving freight mobility and access to regional markets, particularly benefiting logistics, manufacturing, and distribution sectors in counties such as Centre, Blair, and Lycoming. Enhanced connectivity to Interstate 80 via planned high-speed interchanges is projected to support regional freight economies by reducing travel times and enabling more efficient goods movement, thereby attracting industrial investments.[15] Local planning documents identify I-99 as a catalyst for growth, with upgraded highway infrastructure spurring spin-off opportunities in construction, site preparation, and ancillary services during and after build-out phases.[31] Job creation benefits stem from the highway's role in bolstering the I-99 Innovation Corridor, where proximity to institutions like Pennsylvania State University Altoona, Mount Aloysius College, and Saint Francis University provides businesses with access to a skilled workforce—over 22% of adults aged 25 and older in the corridor hold a bachelor's degree or higher. Collaborations between educational entities and industry have strengthened workforce pipelines in fields like advanced manufacturing and technology, contributing to stable employment growth in underserved Appalachian regions.[32] Economic strategies in affected counties, including Centre and Lycoming, emphasize I-99's potential to draw employers by linking rural areas to urban centers like State College and Williamsport, though quantifiable long-term job gains remain tied to broader infrastructure completions rather than the highway alone.[33][34]Cost-benefit analyses and counterarguments
Proponents of Interstate 99's development, including Pennsylvania Department of Transportation (PennDOT) officials and regional economic planners, have argued that upgrades along the corridor generate positive economic returns through enhanced freight movement and induced development in rural areas. A background study for the US 220/Future I-99 corridor in Lycoming County projected that interchanges would spur land development opportunities, potentially increasing property values and attracting logistics and manufacturing investments by improving access to markets in central Pennsylvania and beyond.[34] Similarly, the Appalachian Regional Commission's (ARC) 2017 economic analysis of completing the Appalachian Development Highway System (ADHS), of which Corridor O (incorporating segments of I-99) is a part, estimated that full implementation could yield $22 billion in annual benefits nationwide by 2040, including 175,000 jobs and $15 billion in GDP growth, primarily via reduced travel times and logistics costs for Appalachian communities.[35] These projections rely on input-output models assuming multiplier effects from highway access, though ARC critiques noted that benefits are concentrated in high-traffic corridors and diminish in low-volume rural links like much of I-99. Construction and maintenance costs for I-99 segments have been substantial, often exceeding initial estimates due to terrain challenges and scope expansions. The ongoing high-speed interchange with I-80, critical for I-99's functionality, carries a total cost of $259 million, with construction from 2024 to 2030 involving earthwork, bridges, and ramp realignments to handle projected 20,000+ daily vehicles.[15] Earlier upgrades, such as four-lane widening and safety improvements along US 220 (redesignated I-99), totaled hundreds of millions in federal and state funds from the 1990s onward, funded partly through earmarks in transportation bills like the 1998 TEA-21 Act.[4] No comprehensive benefit-cost ratio (BCR) exceeding 1.0 has been publicly detailed for I-99 as a standalone project; instead, benefits are bundled into broader ADHS evaluations, where ARC's models assume a regional BCR of 1.5-2.0 for corridor completions but caution that isolated segments may underperform without full connectivity.[35] Critics, including fiscal watchdogs and transportation policy analysts, contend that I-99 exemplifies inefficient allocation of federal highway dollars, with benefits overstated relative to costs and alternatives like rail or local road maintenance. The Cato Institute has labeled it the "Bud Shuster Highway," attributing its 1998 designation and funding—secured by then-House Transportation Committee Chairman Bud Shuster (R-PA)—to pork-barrel politics rather than merit, noting low average daily traffic (under 15,000 vehicles in many sections pre-upgrades) and minimal interstate connectivity, which limits national economic spillovers.[5] A 2008 New York Times analysis highlighted debates over renaming efforts to remove Shuster's name, portraying the project as emblematic of earmark-driven spending that prioritized district interests over high-return investments, such as urban congestion relief elsewhere.[24] Counterarguments emphasize opportunity costs: federal funds diverted to I-99 could address higher-BCR needs, like bridge repairs yielding BCRs of 2-5 per the Federal Highway Administration, amid Pennsylvania's $8 billion highway maintenance backlog as of 2023. These views underscore systemic issues in earmark processes, where congressional influence often supplants rigorous economic vetting.Recent developments
2024-2025 infrastructure projects
The Pennsylvania Department of Transportation (PennDOT) launched the I-99 Preservation Project in 2024, targeting a 10-mile segment from the Newry median crossover to 17th Street in Blair County.[36] Valued at $23.4 million and awarded to New Enterprise Stone and Lime, Inc., the initiative encompasses milling, concrete paving, pavement marking, and related preservation measures to extend the roadway's service life, with full completion anticipated by September 2025.[36] [37] Phase Three of the I-80/I-99 high-speed interchange project in Centre County commenced on September 4, 2024, focusing on constructing the direct interchange, including bridges, retaining walls, and connector roads to link I-99 with I-80 via State Route 26.[4] [15] This $260 million effort, part of a broader phased development funded partly through federal infrastructure allocations, prioritizes traffic safety and congestion relief but extends through 2030.[38] [15] Supporting maintenance activities in 2025 included paving crossover lanes along I-99 in Blair County starting September 29, under single-lane restrictions to enable traffic shifts for ongoing work, lasting approximately two weeks.[39] [40] Additional concrete paving, milling, and line painting occurred in the same county through September 2025, aligning with the preservation project's timeline.[37] Lane restrictions persisted into October 2025 for related median and shoulder improvements.[41]Signage and maintenance updates
In March 2025, the Pennsylvania Department of Transportation (PennDOT) announced plans to award a contract for upgrading signage along the northern segment of Interstate 99 (I-99), converting existing U.S. Route 15 shields to I-99 markers from Williamsport northward to the New York state line.[42] This change aligns with the Federal Highway Administration's 2019 approval of I-99 designation for the US 15 corridor, which extends into New York but remains unsigned as I-99 there pending state action.[42] Maintenance efforts in 2025 focused on pavement preservation and safety improvements in Blair County. A paving project along I-99 from the Newry median crossover to the 17th Street exit involved overnight lane restrictions and flagging operations, with work continuing through October 2025 to resurface the roadway and enhance durability.[41] [37] In Bellwood, PennDOT added truck parking spots on an I-99 on-ramp as part of a statewide initiative to create over 1,200 new spaces at 133 locations by late 2025, addressing commercial vehicle overflow.[43] Additional updates included short-term lane closures for median crossover repairs between Newry and 17th Street, scheduled intermittently through October 24, 2025, to minimize disruptions while improving interchange safety.[36] Near State College, traffic stoppages on Shiloh Road in October 2025 affected I-99 ramps, with potential backups during peak hours to facilitate bridge and roadway maintenance.[44] No major signage or maintenance changes were reported in New York for the unsigned I-99 extension along US 15, though general interstate sign updates statewide emphasized mileage-based exits without specific I-99 impacts.[45]Future plans
High-speed interchange with I-80
The high-speed interchange between Interstate 99 (I-99) and Interstate 80 (I-80) is under construction near Bellefonte in Centre County, Pennsylvania, to provide a direct, full-access connection that bypasses the existing at-grade intersection via Pennsylvania Route 26 (PA 26).[15][46] The project encompasses three phases, including new bridges, ramps, and earthwork to support high-speed traffic flow, enhancing regional freight movement and travel reliability by reducing congestion at the current diamond interchange.[15][39] Construction bidding occurred in early November 2023, with active fieldwork commencing on April 1, 2025, following preparatory phases that began in September 2024.[13][15] The total estimated cost is $259 million, funded through state and federal sources, with completion projected for September 2030.[15] As of October 2025, ongoing activities include hauling of fill material—expected to continue through the 2025 season and into 2026—along with paving of crossover lanes on I-99, which began on September 29, 2025, and required temporary lane closures for approximately two weeks.[47][39][48] The interchange will eliminate local traffic weaving on PA 26 and support economic connectivity by linking I-99's north-south corridor directly to I-80's east-west route, though it has prompted local zoning discussions, such as a proposed travel plaza development adjacent to the site in August 2025.[46][49] Portions of Jacksonville Road remain closed until project completion to facilitate ramp construction.[46]Full corridor connection and extensions
The primary objective for completing the Interstate 99 corridor entails upgrading the approximately 55-mile segment of U.S. Route 220 from the current northern terminus of the southern I-99 near Bellefonte, Pennsylvania—adjacent to the pending high-speed interchange with Interstate 80—northward through Lock Haven and Jersey Shore to its junction with U.S. Route 15 near Williamsport. This would establish a continuous interstate-standard route linking the southern segment (from the Pennsylvania Turnpike/I-70 and I-76 near Bedford to Bellefonte) with the northern segment (from I-180 in Williamsport along US 15 through the Pennsylvania-New York state line to I-86 near Corning, New York).[2][4] Pennsylvania Department of Transportation (PennDOT) long-term plans designate this US 220 stretch as future I-99, requiring full divided highway construction, high-speed ramps, and elimination of at-grade intersections to meet Interstate standards. As of October 2025, segments such as the US 220 corridor near Lock Haven have undergone partial widening and safety improvements, but substantial portions remain undivided two-lane roadways, with full upgrades contingent on federal and state funding availability and environmental clearances. No specific completion date exists, though incremental projects, including bridge replacements and lane additions, continue under PennDOT's broader US 220 improvement initiatives.[4][13] A key enabler for northern connectivity is the I-80/I-99 high-speed interchange project near Bellefonte, currently under construction with paving and ramp work ongoing into 2025. Valued at over $200 million, this facility will provide direct, high-speed access between I-99 and I-80 Exit 158 (proposed as B-18), bypassing the existing low-speed PA 26 interchange and facilitating smoother traffic flow toward the planned US 220 upgrades.[15][13] Advancing the northern segment's integration, PennDOT initiated signage changes in late 2024 to designate roughly 40 miles of US 15 from I-180 in Williamsport to the New York border as I-99, aligning with New York's pre-existing I-99 concurrency along the same route since 2013. Contracts for sign fabrication and installation were let in early 2025, with completion expected to enhance route continuity without requiring physical upgrades, as the roadway already meets interstate criteria.[42][4] No active proposals exist for extensions beyond the corridor's endpoints at I-70/I-76 southward or I-86 northward, though advocates have occasionally suggested further links to enhance freight movement between central Pennsylvania and the Southern Tier of New York. Full realization of the corridor would span about 200 miles, serving as a vital north-south artery parallel to but distinct from I-81 and I-81 alternatives.[2][3]Exit list
Pennsylvania exits
Interstate 99 in Pennsylvania maintains exit numbering aligned with its mileage-based reference points, beginning at Exit 1 near the Pennsylvania Turnpike (I-70/I-76) interchange in Bedford County and extending to Exit 83 in Centre County near Bellefonte, covering roughly 85 miles through rural and semi-urban areas of south-central Pennsylvania.[9] The freeway overlays much of U.S. Route 220, providing access to key destinations including Altoona, State College (home to Pennsylvania State University), and regional parks, with interchanges designed for varying speed limits reflecting terrain and traffic volumes.[4] The following table lists the exits from south to north:| Exit | Destinations | Notes |
|---|---|---|
| 1 | I-70/I-76 (PA Turnpike), Pittsburgh, Harrisburg | Partial cloverleaf; toll road access; speed limit 35–40 mph; connects to Business US 220 south.[9] |
| 3 | PA 56, US 220 Bus., Johnstown, Cessna | Diamond interchange; Bedford County Airport nearby; speed limit 35 mph.[9] |
| 7 | PA 869, St. Clairsville, Osterburg | Speed limit 35 mph; low clearance warning (14 ft 1 in).[9] |
| 10 | Blue Knob State Park, Imler | Speed limit 35 mph.[9] |
| 15 | US 220 Bus., Claysburg, King, Sproul | Northbound only in some configurations.[9] |
| 23 | PA 36/PA 164, US 22, Roaring Spring, Portage, Hollidaysburg | Speed limit 30–35 mph; Altoona-Blair County Airport access.[9] |
| 28 | US 22, PA 764, Duncansville, Ebensburg, Hollidaysburg | Ramp speed 25 mph; near Horseshoe Curve.[9] |
| 31 | US 220 Bus., Plank Road | Speed limit 35–40 mph; Blair County Convention Center.[9] |
| 32 | PA 36 (to), Frankstown Road | Speed limit 35 mph; Canoe Creek State Park.[9] |
| 33 | 17th Street, Altoona | Speed limit 30 mph; Railroaders Memorial Museum.[9] |
| 39 | PA 764 (south), Pinecroft | Park and ride lot.[9] |
| 41 | PA 865 (north), Bellwood | Speed limit 40 mph; DelGrosso's Amusement Park.[9] |
| 45 | Tipton, Grazierville | Speed limit 20–30 mph; near Horseshoe Curve.[9] |
| 48 | PA 453, Tyrone, PA 550 (to), Huntingdon | Speed limit 20 mph; near Horseshoe Curve.[9] |
| 52 | PA 350, US 220 Bus., Bald Eagle, Philipsburg | .[9] |
| 61 | US 220 Alt./US 322 (west), Port Matilda, Philipsburg | Northbound; speed limit 30 mph; Black Moshannon State Park.[9] |
| 62 | US 322 (west), Philipsburg | .[9] |
| 68 | Waddle, Grays Woods, PA 550 (to) | Speed limit 25–40 mph.[9] |
| 69 | US 322 Bus. (east), Atherton Street | Speed limit 40–45 mph.[9] |
| 71 | Toftrees, Woodycrest | Speed limit 35 mph.[9] |
| 73 | US 322 (east), Mount Nittany Expressway, State College | Pennsylvania State University access.[9] |
| 74 | Innovation Park, Pennsylvania State University | Speed limit 35 mph.[9] |
| 76 | Shiloh Road, Nittany Mall | Speed limit 25–35 mph.[9] |
| 78A | PA 150 (south) | Speed limit 30 mph; State Correctional Institution.[9] |
| 78B | PA 150 (north), Bellefonte | Speed limit 30 mph.[9] |
| 80 | Harrison Road | Northbound only; no re-entry northbound; speed limit 35 mph.[9] |
| 81 | PA 26 (south)/PA 64, Pleasant Gap | Speed limit 35 mph.[9] |
| 83 | PA 550, Bellefonte, Zion | Speed limit 25 mph; northern terminus of signed I-99 freeway segment.[9] |
New York extensions
Interstate 99 enters New York from Pennsylvania concurrent with U.S. Route 15, traversing approximately 12 miles through the Southern Tier region of Steuben County to its northern terminus at a trumpet interchange with Interstate 86 (I-86) and New York Route 17 (NY 17) in Painted Post.[10] The route was upgraded to full interstate standards, including reconstruction of the I-86/NY 17 interchange, relocation of NY 417, and conversion to mile-based exit numbering, with the I-99 designation officially applied on June 27, 2014.[10] [50] This segment serves as a connector between central Pennsylvania and the Southern Tier Expressway (I-86/NY 17), facilitating travel toward Corning and Binghamton to the east or Jamestown and Rochester to the west.[10] The following table lists the exits along I-99/US 15 in New York, based on northbound mileposts from the state line.[10]| Mile | Exit | Destinations | Notes |
|---|---|---|---|
| 0.00 | — | Pennsylvania state line | Southern terminus of I-99 in New York; speed limit 65 mph northbound, 70 mph southbound.[10] |
| 6.41 | 6 | CR 5 – Presho | Northbound exit and entrance only; formerly Exit 1.[10] |
| 8.23 | 8 | NY 417 – Erwin, Addison | Northbound exit and entrance only; formerly Exit 2.[10] |
| 9.60 | — | Parking area, Text Stop | Southbound only.[10] |
| 11.09 | 11 | NY 417 – Gang Mills, Painted Post | Formerly Exit 3; southbound signed for Gang Mills only.[10] |
| 12.13 | 12 | I-86 west – Jamestown, Rochester | Northbound exit and southbound entrance; southbound signed for Robert Dann Drive.[10] [3] |
| 12.13 | 13A-B | I-86 east/NY 17 east/NY 352 – Corning, Binghamton; I-99/US 15 south | Northern terminus of I-99; formerly Exits 4A (east) and 4B (south).[10] [50] |