Interstate 676
Interstate 676 is a 6.90-mile auxiliary Interstate Highway spanning Pennsylvania and New Jersey, functioning as an urban connector between two points along Interstate 76 by traversing Center City Philadelphia via the Vine Street Expressway and crossing the Delaware River on the Benjamin Franklin Bridge before proceeding through Camden to its southern terminus near the Walt Whitman Bridge.[1][2] The route originates at the interchange with I-76 and U.S. Route 30 in Philadelphia's Schuylkill neighborhood, proceeds eastward in a mostly depressed alignment through downtown—facilitating high-volume regional traffic with approximately 106,000 vehicles daily on its core segment—before ascending to the bridge and curving southward in New Jersey to end at I-76 in Gloucester City.[3][4] Conceived in the mid-20th century amid broader urban highway expansions to accommodate growing automobile dependency, construction of the Vine Street portion advanced incrementally from the late 1950s, with the full east-west linkage to I-95 and completion of the Philadelphia segment delayed until January 1991 due to persistent community opposition, including concerns over displacement in neighborhoods like Chinatown and the unearthing of historic Black burial grounds during excavation.[5][6][7] As a critical artery in the Philadelphia region's infrastructure, I-676 alleviates congestion on parallel surface streets and supports commerce between Pennsylvania and South Jersey, though its elevated and sunken design has drawn criticism for severing urban fabric and exacerbating local traffic bottlenecks at interchanges.[8][9]Route description
Pennsylvania
Interstate 676 follows a 2.16-mile course through Philadelphia, Pennsylvania, as an urban east-west freeway designated as the Vine Street Expressway concurrent with U.S. Route 30. It originates at a trumpet interchange with Interstate 76/U.S. Route 30 (Schuylkill Expressway) on the west bank of the Schuylkill River and proceeds eastward through Center City Philadelphia, mostly as a six-lane depressed highway below the local street grid, before rising to connect with the Benjamin Franklin Bridge over the Delaware River into New Jersey. The route lacks mile-based exit numbers and serves as a critical link bypassing downtown congestion for traffic between the Pennsylvania Turnpike (I-76), points west, and destinations across the Delaware River or along I-95.[3][9] Eastbound, I-676 separates from I-76/U.S. 30 at the western terminus and immediately encounters an exit for 22nd Street, providing access to the Benjamin Franklin Parkway, Fairmount Park, and the Philadelphia Museum of Art. The freeway then passes beneath the grid streets with stone-arch overpasses and adjacent service roads in sections, next offering an exit for Broad Street (Pennsylvania Route 611), connecting to the Pennsylvania Convention Center, City Hall, and central business districts. Further east, an interchange serves 15th Street and 8th Street/Franklin Square, linking to Penn's Landing and the historic district. Beyond these, I-676 meets Interstate 95 at a directional T-interchange east of 10th Street, with ramps to I-95 south toward Philadelphia International Airport, Chester, and Wilmington, Delaware, and to I-95 north toward Trenton, New Jersey, and New York City; no direct eastbound continuation from I-95 joins I-676 here. The route then elevates briefly, merging traffic from 6th Street before ascending onto the eight-lane Benjamin Franklin Bridge, which carries I-676/U.S. 30 across the Delaware River into Camden, New Jersey.[3][9][10] The Vine Street Expressway portion features three 12-foot lanes in each direction, eight-foot shoulders, and a median barrier or curb in places, with landscaping and parkway-like elements in earlier sections completed in the 1950s. Service roads parallel the mainline between 18th Street and Broad Street, accommodating local access. The segment handles approximately 106,000 vehicles daily, underscoring its role in regional mobility despite urban density and historical construction delays.[9][4]
New Jersey
Upon crossing the Delaware River from Philadelphia via the Benjamin Franklin Bridge, Interstate 676 enters Camden County, New Jersey, and continues southward as a six-lane urban freeway known as the northern segment of the North-South Freeway.[11] This 4.75-mile portion provides direct access between downtown Philadelphia and central Camden, facilitating commuter and regional traffic flows.[11] Immediately after the bridge, the route passes through industrial and residential areas of Camden with an interchange at Morgan Boulevard (Exit 1A) for local access.[12] Further south, I-676 intersects with CR 537 (Exit 2) near the Camden waterfront, offering connections to nearby neighborhoods and the Delaware River Port Authority facilities.[12] The freeway then curves slightly westward through downtown Camden, with exits for Martin Luther King Jr. Boulevard (Exit 3) serving government buildings and Rutgers University–Camden, followed by an interchange at Dr. Martin Luther King Jr. Boulevard extended (Exit 4A/B).[13] The route terminates at a trumpet interchange with Interstate 76 (Exit 5) in Gloucester City, adjacent to the Walt Whitman Bridge, where northbound traffic merges onto I-76 toward the Walt Whitman Bridge and southbound continues as I-76 west.[11] Throughout its length in New Jersey, I-676 maintains full control-of-access with concrete barriers and service roads in urban sections to manage high traffic volumes.[14]Technical features
Physical characteristics
Interstate 676 extends 6.9 miles (11.1 km) from its western terminus at a cloverleaf interchange with Interstate 76 and U.S. Route 30 in Philadelphia, Pennsylvania, eastward across the Delaware River to its eastern terminus at Interstate 76 in Gloucester City, New Jersey.[15] The route functions as an urban auxiliary freeway, designated as part of the National Highway System throughout its length.[3] In Pennsylvania, the highway comprises the 1.75-mile Vine Street Expressway, a sunken six-lane divided freeway that parallels the former Vine Street alignment through Center City Philadelphia.[5] This section features three 12-foot-wide lanes in each direction, eight-foot shoulders, and a narrow median barrier.[9] The expressway includes complex interchanges, such as a directional stack interchange with Interstate 95, and passes beneath multiple overpasses carrying local streets. Grade-separated connections predominate, though the eastern approaches to the Delaware River crossing incorporate signalized at-grade intersections.[16] The route crosses the Delaware River on the Benjamin Franklin Bridge, a suspension bridge originally constructed between 1922 and 1926 with a total length of approximately 8,300 feet (2,530 m) and main span of 1,750 feet (533 m).[3] The bridge accommodates six lanes of Interstate 676 traffic, with a vertical clearance of about 135 feet (41 m) above mean high water under normal conditions, though movable maintenance walkways can reduce this to 121 feet (37 m) in the central span.[17][18] In New Jersey, Interstate 676 continues southeastward for roughly 2 miles as an elevated and at-grade six-lane freeway through Camden, known locally as the North-South Freeway or Martin Luther King Jr. Boulevard extension.[3] This segment includes a partial cloverleaf interchange with U.S. Route 30 and terminates at a trumpet interchange with Interstate 76. The entire route maintains limited-access freeway standards, with concrete pavement and steel girder bridges spanning urban obstacles.[9]Engineering elements
Interstate 676 consists primarily of a six-lane depressed expressway in Philadelphia, constructed using cut-and-cover methods to minimize surface disruption in the urban core, with depths reaching up to 30 feet below street level in sections.[8] This design incorporates extensive retaining walls—totaling 41 structures—to support the excavation and prevent soil collapse, engineered for high seismic and load-bearing resilience despite the region's low seismic activity.[8] Service roads parallel the mainline, featuring stone-arch overpasses that evoke early 20th-century parkway aesthetics, enhancing visual integration with surrounding historic districts.[9] The route includes multiple viaduct and ramp structures for interchanges, notably elevated ramps transitioning from the depressed Vine Street section to the Benjamin Franklin Bridge approaches, spanning approximately 1,750 feet in elevation gain to align with the bridge deck.[9] Recent engineering upgrades, such as the replacement of seven 1950s-era prestressed concrete bridges spanning the expressway between 18th and 22nd Streets, utilized single-span steel girder designs to achieve 16-foot vertical clearances, accommodate utility relocations, and support enhanced pedestrian amenities including thicker decks for landscaping loads.[19][20] These reconstructions employed accelerated precast slab systems for rapid installation, reducing lane closure times during maintenance.[21] The Benjamin Franklin Bridge segment, integral to I-676, is a steel-wire suspension bridge with a main span of 1,750 feet and total structure length of 8,170 feet, featuring a roadway width of 77.8 feet accommodating seven lanes of interstate traffic plus rail tracks and sidewalks.[22] Engineered by Ralph Modjeski and opened in 1926, it incorporates stiffening trusses to mitigate wind-induced oscillations, with a 1984 rehabilitation reinforcing towers and suspenders to handle modern traffic volumes exceeding 100,000 vehicles daily.[22] In New Jersey, the route terminates with short approach viaducts linking to local arterials, designed for seamless interstate continuity.[23]History
Planning and proposals (1940s–1960s)
In the aftermath of World War II, Philadelphia faced increasing traffic congestion exacerbated by the opening of the [Benjamin Franklin Bridge](/page/Benjamin Franklin Bridge) in 1926, prompting city planners to prioritize expressway development. In 1945, the Philadelphia City Planning Commission proposed a depressed six-lane expressway along Vine Street as part of the city's postwar redevelopment plan, featuring parallel service roads, stone-arch bridges over cross streets, and parkway-style landscaping to mitigate urban disruption. This alignment was envisioned to connect the proposed Delaware Expressway (later I-95) eastward with the Schuylkill Expressway (later I-76) westward, including interchanges at Broad Street, at an estimated cost of $26 million.[9][24] The proposal gained traction amid national momentum for highway expansion, with the Pennsylvania Department of Highways approving the Vine Street plan in 1949, initiating preliminary widening of the existing street through demolitions of substandard buildings in a block-wide swath. By 1951, Vine Street had been expanded to ten lanes to accommodate interim traffic growth. In 1950, the Planning Commission refined the route specifications: three 12-foot lanes in each direction separated by an 8-foot shoulder and a 4-foot median with reflectorized curb, designed for a 50 mph speed limit and 14-foot vertical clearances, with service roads planned from 18th Street to Broad Street to preserve local access; projections anticipated 25,000 vehicles per day by 1970.[9][24] The 1956 Federal-Aid Highway Act formalized the Interstate Highway System, incorporating Vine Street into federal planning as a critical crosstown link. Initially proposed for designation as I-895 in 1958 to extend from the Schuylkill Expressway toward the Benjamin Franklin Bridge, the route underwent number revisions, including I-380 and I-80S, before settling toward its eventual I-676 label. In the mid-1960s, proposals advanced for the eastern extension from 16th Street to the bridge approach, maintaining a depressed six-lane profile with one-way service roads; public hearings in March 1966 addressed design adjustments to protect historic properties and enhance aesthetics, reflecting growing scrutiny over urban impacts.[9][24]Construction phases and delays (1970s–1980s)
Construction of the eastern extension of the Vine Street Expressway, intended to connect from 18th Street eastward to Interstate 95 and the Benjamin Franklin Bridge, stalled after initial western segments opened in the late 1950s. New federal environmental regulations enacted in the early 1970s required re-evaluation of pre-1969 highway projects, prompting the Federal Highway Administration (FHWA) in July 1973 to mandate comprehensive reviews for ongoing plans like I-676's extension.[9] In November 1973, the FHWA specifically directed Pennsylvania officials to prepare a new environmental impact statement (EIS) for the Vine Street project, citing deficiencies in prior assessments of air quality, noise pollution, and urban impacts that had been overlooked in earlier planning.[24][9] The revised EIS, released in 1977, incorporated alternatives such as enhanced transit options and measures to mitigate quality-of-life effects on adjacent neighborhoods, including Chinatown and historic areas like Franklin Square.[24] However, persistent community opposition—fueled by concerns over displacement, noise, and barrier effects on urban fabric—along with protracted public hearings and iterative design revisions, prevented construction from advancing through the late 1970s and most of the 1980s.[24][9] These delays narrowed the planned expressway width in some segments to preserve structures like churches, reflecting concessions to preservationists amid broader urban renewal critiques.[5] Progress resumed only in 1986 when Pennsylvania Governor Robert Casey approved funding and revived the project, initiating the final construction phase from 16th Street eastward.[9] This phase included building a depressed four-lane mainline with shoulders, service roads, and a directional-T interchange at I-95, but it faced ongoing logistical challenges in a dense urban corridor already burdened by interim at-grade traffic congestion.[9] The combination of regulatory hurdles, fiscal constraints, and local resistance extended the timeline from initial 1960s proposals to near-completion in the early 1990s, underscoring the tensions between interstate highway mandates and evolving environmental and social priorities.[24][9]Completion and ribbon cuttings (1990–1991)
The final segment of the Vine Street Expressway in Philadelphia, connecting to the Benjamin Franklin Bridge and completing Interstate 676's route through the city, opened to traffic on January 10, 1991, after decades of planning, construction phases, and legal delays.[24] The Pennsylvania Department of Transportation (PennDOT) organized a ribbon-cutting ceremony at 10:00 a.m. that day to mark the occasion, finalizing the east-west link from the Schuylkill Expressway (I-76) to the Delaware River.[25] This completion addressed longstanding traffic bottlenecks in Center City, reducing anticipated peak-hour travel times across the city from 30 minutes to under 10 minutes, as projected by engineers.[5] A subsequent direct ramp connection to Interstate 95 (Delaware Expressway) opened approximately six months later in mid-1991, fully integrating I-676 into the regional highway network and enabling seamless interstate travel without surface street interruptions.[24] PennDOT's efforts in 1990 focused on paving, barrier installation, and signage for the six-lane depressed highway, overcoming prior opposition from urban renewal impacts and community displacement in areas like Chinatown.[6] The 1.75-mile facility, built at a cost exceeding initial estimates due to phased funding and litigation, carried an initial average daily traffic volume of over 100,000 vehicles upon opening, underscoring its immediate role in freight and commuter mobility.[5]Operational impacts
Transportation and economic benefits
Interstate 676 functions as a key east-west linkage in the Philadelphia region's highway network, connecting the Schuylkill Expressway (I-76) to Interstate 95 and the Benjamin Franklin Bridge over the Delaware River. This alignment allows for direct routing of through-traffic, bypassing portions of surface streets in central Philadelphia and providing access to northern New Jersey via subsequent connections like the New Jersey Turnpike. The highway accommodates approximately 106,000 vehicles per day across its 1.75-mile length in Pennsylvania, reflecting its central role in handling both commuter flows and commercial vehicles within the urban core.[4] The Benjamin Franklin Bridge segment of I-676 carries about 100,000 vehicles daily, supporting cross-river mobility between Philadelphia and Camden. This volume includes substantial patronage from daily commuters and transit users via the integrated PATCO Speedline, which parallels the roadway. By enabling reliable interstate travel, the route reduces average traversal times for regional journeys compared to pre-expressway alternatives reliant on at-grade roads.[26] In economic terms, I-676 bolsters freight logistics by offering a controlled-access path to Camden's industrial zones and port terminals, linking them to Philadelphia's South Philadelphia cargo facilities and broader interstate corridors. This infrastructure facilitates the efficient transport of goods, including containerized shipments and bulk commodities, contributing to the Delaware Valley's role as a hub for manufacturing, distribution, and interregional trade between Pennsylvania and New Jersey. State freight assessments highlight the route's utility in serving port-related commerce, which underpins local employment in logistics and related sectors.[27]
Urban and social effects
The operation of Interstate 676, particularly its Vine Street Expressway segment in Philadelphia, has created enduring physical barriers that fragment urban neighborhoods and impede pedestrian connectivity. Completed in 1991, the depressed highway bisected Chinatown, dividing the community into isolated northern and southern halves and stunting organic development by severing street-level links to surrounding areas like Center City.[5] [28] This division persists as a concrete moat, with over 100,000 vehicles traversing the corridor daily, elevating risks to foot traffic and constraining local economic vitality through reduced walkability.[29] [30] In Camden, New Jersey, the North-South Freeway extension of I-676 halved downtown in the 1960s–1980s construction era, demolishing blocks and fostering long-term urban decay by prioritizing vehicular throughput over cohesive community spaces.[31] The resulting elevated and at-grade infrastructure has perpetuated socioeconomic silos, particularly affecting lower-income and minority populations by limiting access to jobs, services, and social networks across the divided zones.[32] Socially, these effects manifest in heightened noise pollution, air quality degradation from exhaust, and public health strains in proximate residences, as evidenced by community reports of elevated respiratory issues and disrupted daily interactions.[28] While enabling regional mobility, the highway's design has causally reinforced car dependency, marginalizing transit users and pedestrians in an already dense urban matrix, with no comprehensive mitigation until recent capping proposals.[5][33]Controversies
Community opposition and legal challenges
Community opposition to the Vine Street Expressway (Interstate 676) emerged prominently in the 1960s, particularly from Philadelphia's Chinatown residents, who protested the proposed route's potential to bisect the neighborhood, demolish homes and businesses, and sever connections to key institutions like Holy Redeemer Chinese Catholic Church and School.[5][6] These concerns centered on the disruption of social cohesion, increased noise and air pollution, and the irreversible alteration of a densely populated urban fabric, leading to organized demonstrations and advocacy against the project's alignment through the mid-1970s.[6] By the mid-1970s, vehement resistance from Chinatown groups prompted design modifications, including a reduction in the expressway's width to preserve nearby historic structures and a shift to a depressed (trench) configuration in sensitive areas to minimize surface-level barriers, though these concessions did not fully satisfy critics who argued the highway would still fragment the community.[5] Opposition also highlighted broader urban renewal failures, with the project exacerbating displacement in adjacent historic Black neighborhoods, where construction later uncovered unmarked graves from two First African Baptist Church cemeteries in the 1980s, further stalling progress amid ethical and logistical disputes over remains relocation.[7] Legal challenges intensified in the 1980s, exemplified by Vine Street Concerned Citizens, Inc. v. Dole (1985), in which plaintiffs sought a preliminary injunction to halt pre-construction and construction activities pending a supplemental Environmental Impact Statement under the National Environmental Policy Act, citing unaddressed changes to the original project scope that amplified displacement of community resources and environmental harms.[34] The U.S. District Court for the Eastern District of Pennsylvania evaluated the equities but ultimately did not grant the injunction, allowing work to continue despite acknowledged trade-offs in avoiding "unacceptable displacement of significant community resources."[34] These combined pressures, alongside funding and political hurdles, contributed to multi-decade delays, with initial segments opening in 1980 and full completion only in November 1991.[5][6]Displacement and cultural losses
The construction of Interstate 676, known as the Vine Street Expressway, resulted in the displacement of numerous residents and businesses, particularly in Philadelphia's Chinatown neighborhood, where significant portions were demolished during the widening of Vine Street in the 1950s and subsequent expressway development in the 1970s through 1991.[33] This included the removal of homes and commercial structures that fragmented the community, severing connections between Chinatown and the adjacent Chinatown North area.[35] Community opposition, voiced since the 1960s, highlighted the socioeconomic and cultural disruptions, including the proposed demolition of historic sites such as Holy Redeemer Church, though sustained protests mitigated some threats while the highway still proceeded.[36][5] Culturally, the expressway's elevated and depressed sections erased parts of Philadelphia's urban fabric, including remnants of the historic Skid Row district along Vine Street, which had been a notable social landscape in the early 20th century before initial 1950s demolitions for precursor projects.[37] The barrier effect persists, contributing to long-term isolation of ethnic enclaves and loss of neighborhood cohesion, with over 100,000 daily vehicles exacerbating noise, air pollution, and visual severance that hindered cultural continuity and pedestrian access.[29] These impacts were part of broader federally funded highway initiatives in Philadelphia, which displaced approximately 14,000 families citywide by the late 1960s through urban renewal and freeway construction, though Vine Street-specific figures remain less precisely documented.[32]Recent and future developments
Maintenance projects
In 2009, the Pennsylvania Department of Transportation (PennDOT) undertook pavement repairs on the Vine Street Expressway segment of I-676, addressing deteriorated concrete through the installation of precast concrete slabs to restore structural integrity and extend service life, with all lanes reopened by late that year.[21] A major bridge reconstruction project commenced in April 2015, replacing six aging 1950s-era concrete bridges spanning I-676 between 18th and 22nd Streets with single-span steel plate girder structures to improve load capacity, vertical clearance, and seismic resilience while reusing existing abutments and relocating utilities such as steam pipes.[38] The effort, involving 2,846 tons of steel and customized designs for skewed alignments and heavy utility loads, was completed in 2018, ahead of initial projections in some phases.[19] In January 2024, PennDOT conducted barrier repairs on I-676 in Center City Philadelphia, closing a left lane on eastbound sections between Broad Street and the Vine Street on-ramp over a weekend to address damage and enhance safety features.[39] Ongoing utility maintenance in 2025 included nighttime fiber optic cable repairs on I-676 in Center City, starting October 16, to sustain communication infrastructure reliability amid urban traffic demands.[40] These interventions reflect PennDOT's focus on preserving the corridor's functionality despite its elevated age and high-volume usage.Proposed mitigations like capping
The Chinatown Stitch project, initiated by the City of Philadelphia in 2023, proposes capping approximately 2.5 blocks of the Vine Street Expressway (I-676) between 10th and 13th Streets to reconnect divided sections of Chinatown, addressing the highway's role in fragmenting the neighborhood since its construction in the 1970s and 1990s.[33] The initiative includes constructing a concrete deck over the depressed roadway to create public green space, pedestrian pathways, and potential sites for affordable housing or community facilities, aiming to reduce noise pollution, improve air quality, and restore street-level connectivity.[41] In September 2023, the city presented three conceptual designs—ranging from a full three-block cap to partial two-block coverings with apertures for light and ventilation—following community input, with the selected two-block-plus variant emphasizing parkland and redevelopment opportunities.[42] The project secured $158 million from the federal Reconnecting Communities Pilot Program in March 2024, supplemented by local matching funds, though implementation faced potential delays as of July 2025 amid shifts in federal transportation priorities under the incoming Trump administration.[43][44] Broader proposals under the Cap 676 initiative, a community-driven effort launched around 2020, advocate for a continuous "lid" of parks and amenities spanning much of I-676's urban length in Philadelphia, extending beyond Chinatown to knit together Center City neighborhoods severed by the expressway's trench.[45] An engineering assessment by Urban Engineers and Pennoni, commissioned by the Center City District, evaluated structural feasibility for capping, estimating costs in the hundreds of millions while projecting benefits like increased property values, enhanced walkability, and economic revitalization through new developable land.[46] These mitigations draw from earlier studies, such as a 2016 U.S. Department of Transportation collaboration identifying partial decking and noise abatement as viable low-cost interventions to lessen the highway's barrier effects on pedestrian access and local commerce.[47] Additional proposed measures include small-scale urban treatments like vegetated noise barriers and elevated walkways, as outlined in the Every Place Counts Design Challenge, which prioritized non-structural enhancements to mitigate I-676's ongoing severance of community fabric without full reconstruction.[48] Community outreach, including pop-up events in 2025, continues to refine these plans, with emphasis on equitable benefits for historically displaced residents, though critics note potential construction disruptions and funding uncertainties as barriers to realization.[49] As of October 2025, no construction has commenced, with designs advancing toward environmental reviews and secured grants totaling over $160 million supporting phased implementation.[50]Exit list
Pennsylvania
Interstate 676 follows a 2.16-mile course through Philadelphia, Pennsylvania, as an urban east-west freeway designated as the Vine Street Expressway concurrent with U.S. Route 30. It originates at a trumpet interchange with Interstate 76/U.S. Route 30 (Schuylkill Expressway) on the west bank of the Schuylkill River and proceeds eastward through Center City Philadelphia, mostly as a six-lane depressed highway below the local street grid, before rising to connect with the Benjamin Franklin Bridge over the Delaware River into New Jersey. The route lacks mile-based exit numbers and serves as a critical link bypassing downtown congestion for traffic between the Pennsylvania Turnpike (I-76), points west, and destinations across the Delaware River or along I-95.[3][9] Eastbound, I-676 separates from I-76/U.S. 30 at the western terminus and immediately encounters an exit for 22nd Street, providing access to the Benjamin Franklin Parkway, Fairmount Park, and the Philadelphia Museum of Art. The freeway then passes beneath the grid streets with stone-arch overpasses and adjacent service roads in sections, next offering an exit for Broad Street (Pennsylvania Route 611), connecting to the Pennsylvania Convention Center, City Hall, and central business districts. Further east, an interchange serves 15th Street and 8th Street/Franklin Square, linking to Penn's Landing and the historic district. Beyond these, I-676 meets Interstate 95 at a directional T-interchange east of 10th Street, with ramps to I-95 south toward Philadelphia International Airport, Chester, and Wilmington, Delaware, and to I-95 north toward Trenton, New Jersey, and New York City; no direct eastbound continuation from I-95 joins I-676 here. The route then elevates briefly, merging traffic from 6th Street before ascending onto the eight-lane Benjamin Franklin Bridge, which carries I-676/U.S. 30 across the Delaware River into Camden, New Jersey.[3][9][10] The Vine Street Expressway portion features three 12-foot lanes in each direction, eight-foot shoulders, and a median barrier or curb in places, with landscaping and parkway-like elements in earlier sections completed in the 1950s. Service roads parallel the mainline between 18th Street and Broad Street, accommodating local access. The segment handles approximately 106,000 vehicles daily, underscoring its role in regional mobility despite urban density and historical construction delays.[9][4]