Skyline is a light metro rapid transit system in the City and County of Honolulu on the island of Oʻahu, in the state of Hawaiʻi. Segment 1 of the project, which lies entirely outside of the Urban Honolulu census-designated place, opened on June 30, 2023 linking East Kapolei (on the ʻEwa Plain) and Aloha Stadium in Hālawa. Segment 2, connecting to Pearl Harbor, Daniel K. Inouye International Airport and Middle Street, opened on October 16, 2025. Segment 3, continuing the line across Urban Honolulu to Downtown, is due to open in 2031. The construction of Skyline constitutes the largest public works project in Hawaiʻi's history.
The , automated fixed-guideway line was planned, designed, and constructed by the Honolulu Authority for Rapid Transportation (HART), a semi-autonomous government agency. Hitachi Rail, who also built the railcars used on the line, operates Skyline for the Honolulu Department of Transportation Services (which also manages the island's TheBus service). The almost entirely elevated line is the first large-scale, publicly run metro in the United States to feature platform screen doors and driverless trains. In , the line had an annual ridership of , or about per day as of , compared to the 25,000 per day that was predicted in 2023.
History Plans for a mass transit line to connect Honolulu's urban center with outlying areas began in the 1960s, but funding was not approved until 2005. Debate over the development of a rail system in Honolulu has been a major point of contention in local politics, especially leading into the 2008, 2012, and 2016 mayoral elections. Controversy over the rail line was the dominant issue for local politics in the late 2000s, and culminated in a city charter amendment which left the final decision to a direct vote of the residents of Oʻahu. Construction of the rail line was approved by 53% of voters in November 2008, and ground broke on project construction on February 22, 2011.
Previous projects For more than 50 years, some Honolulu politicians have attempted to construct a rail transit line. In 1966, then-mayor Neal S. Blaisdell suggested a rail line as a solution to alleviate traffic problems in Honolulu, stating, "Taken in the mass, the automobile is a noxious mechanism whose destiny in workaday urban use is to frustrate man and make dead certain that he approaches his daily occupation unhappy and inefficient."
Frank Fasi was elected to office in 1968, and started planning studies for a rail project, (Note: At this time, the Honolulu Star-Bulletin and Honolulu Advertiser published Sunday editions jointly under the name Honolulu Star-Bulletin & Advertiser.) named Honolulu Area Rapid Transit (HART), in 1977. After Fasi lost the 1980 reelection to Eileen Anderson, President Ronald Reagan cut off funding for all upcoming mass transit projects, which led Anderson to cancel HART in 1981. Fasi defeated Anderson in their 1984 rematch and restarted the HART project in 1986, but this second effort was stopped in a 1992 vote by the Honolulu City Council against the necessary tax increase.
Fasi resigned in 1994 to run for governor, with Jeremy Harris winning the special election to replace him. Harris unsuccessfully pursued a bus rapid transit project as an interim solution until he left office in 2004. His successor, Mufi Hannemann, began the Honolulu High-Capacity Transit Corridor Project (HHCTCP), the island's fourth attempt to build a mass transit system operating in a dedicated right-of-way.
Hannemann thought it was "prudent to move quickly" to show the FTA that Honolulu was committed to the HHCTCP. An environmental impact study had not been completed at the time of signing the first construction contract with Kiewit. The FTA needed a complete environmental impact statement before moving Honolulu forward in the grant-awarding process. Hannemann's urge to move fast in the project ultimately allowed stakeholders to delay some important foundational work such as the environmental impact study.
Studies
The City and County of Honolulu Department of Transportation Services released the first formal study related to the HHCTCP on November 1, 2006, the Alternatives Analysis Report. The report compared the cost and benefits of a "fixed guideway system", along with three alternatives. The first expanded the existing bus system to match population growth. A second option called for a further expansion to the bus system, with improvements to existing roads. The third alternative proposed a two-lane flyover above the H-1 freeway between Pearl City and Honolulu International Airport, continuing over Nimitz Highway, and into downtown Honolulu. The report recommended construction of the fixed guideway, and is considered the city's official justification for building a rail line.City and County of Honolulu Department of Transportation Services (November 1, 2006), Honolulu High-Capacity Transit Corridor Alternatives Analysis Report Chapter 1, Chapter 2, Chapter 3 to 7, retrieved February 25, 2009
A second planning document, the Draft Environmental Impact Statement (DEIS), studied possible natural and social impacts of the construction and operation of the HHCTCP. The DEIS was completed and cleared for public release by the Federal Transit Administration (FTA) on October 29, 2008. After minor changes were made to comply with state law, the document was distributed via the city's official project website four days later. The DEIS indicated that impacts of the rail project would include land acquisition from private owners on the route, displacement of residents and businesses, aesthetic concerns related to the elevated guideway, and noise from passing trains.U.S. Department of Transportation Federal Transit Administration; City and County of Honolulu Department of Transportation Services, Draft Environmental Impact Statement Executive Summary (PDF), retrieved February 25, 2009
The city was criticized for timing the release only two days before the 2008 general election. City Councilmember Ann Kobayashi, running as a mayoral candidate against incumbent Hannemann, suggested that the city deliberately withheld key information to early voters who had already cast their ballots for the mayoral candidates, and a city charter amendment related to the project. The anti-rail advocacy group Stop Rail Now criticized the report for not further discussing bus rapid transit and toll lanes, options studied earlier by the city in its Alternatives Analysis.U.S. Department of Transportation Federal Transit Administration; City and County of Honolulu Department of Transportation Services (2008-11), Honolulu High-Capacity Transit Corridor Project Draft Environmental Impact Statement/Section 4(f) Evaluation Cover to Contents, Chapter 1 , Chapter 2 , Chapter 3, Chapter 4 (Part 1) , Chapter 4 (Part 2), Chapter 5, Chapters 6–8 , References to Index , Appendix A (Conceptual Alignment Plans and Profiles) , Appendix B (Conceptual Right-of-Way Plans), Appendix C (Construction Approach) , Appendix D (Record of Agency Correspondence and Coordination), Appendix E (Record of Public and Stakeholder Correspondence and Coordination) , retrieved on January 5, 2009
The third and final official planning document, the Final Environmental Impact Statement (FEIS), was approved and cleared for public release by the FTA on June 14, 2010. The FEIS addresses and incorporates public comments received regarding the DEIS. The FTA subsequently declared the environmental review process complete in a record of decision issued on January 18, 2011.
Native burials Like most major infrastructure work in Hawaiʻi, construction of the rail line was likely to uncover historic human remains, notably in its downtown Honolulu section. The Oʻahu Island Burial Council (part of the State Historic Preservation Division, within the State of Hawaiʻi Department of Land and Natural Resources) refused to sign a programmatic agreement on October 21, 2009, over concerns about likely burial sites located along the line's proposed route over Halekauwila Street in Kakaʻako. Three construction projects in the area since 2002 have each encountered unforeseen human remains that led to delays, and archaeologist Thomas Dye stated, "The council is absolutely right that you should expect to find burials on Halekauwila Street".
The Burial Council's core contention was the city's decision to conduct an archaeological survey of the rail line's route in phases, meaning construction on a majority of the line will be complete by the time the survey in the Kakaʻako area is performed, which in turn would increase the likelihood that any remains discovered would be moved instead of being allowed to remain in situ. In response to the Burial Council's concerns, the city agreed to begin conducting an archaeological survey of the area in 2010, two years earlier than originally planned. The state Department of Land and Natural Resources later signed the city's programmatic agreement on January 15, 2011, over the continuing concerns of the Burial Council.
The city's decision to conduct the archaeological survey in phases subsequently led to a lawsuit filed on February 1, 2011, by the Native Hawaiian Legal Corporation on behalf of cultural practitioner Paulette Kaleikini. The suit, which named both the city and the State of Hawaiʻi as defendants, contended that state law required the full length of the rail line to have an archaeological survey conducted before any construction took place, and sought to void the environmental impact statement and all construction permits issued for the project. Kaleikini's lawyers filed on February 18 a request for an injunction to stop work on the project until the case was resolved. The suit was initially dismissed in March 2011 by Circuit Court Judge Gary Chang. However, after Kaleikini's lawyers appealed, the Hawaiʻi Supreme Court ruled in August 2012 in the plaintiff's favor, finding that the State Historic Preservation Division did not comply with state law when it approved the project. The case was then remanded to Circuit Court. In December 2012, the United States District Court for the District of Hawaii granted the plaintiffs' injunction, and ordered that all construction-related activities be halted until compliance with the Hawaiʻi Supreme Court decision was met. Judge Tashima, the sitting judge on the case, ruled that the city is required to file periodic status updates on their compliance with the judgment. The injunction would then terminate 30 days after defendants filed a notice of final compliance.
In February 2013, the rail authority said that they had completed the required archaeological surveys and that construction would resume later that year. The agency reported that remains were discovered at seven sites in the downtown area, and that if it was decided to leave them in place, then they "would be able to adjust the final design to accommodate that request".
Impact on Honolulu mayoral elections