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Project Information + Documents

Build Alternatives

Honoapiilani Project Area Alternatives Map (October 2023)Click Map to Enlarge

Proposed alignments, adapted from the Maui County's Pali to Puamana Plan, converge at serval points in two distinct areas, where the alignments differ from one another, Olowalu and Ukumehame.

The preferred alternative may be selected from two differing proposed alternatives one in each of the two differing areas.


ALTERNATIVE 1 (Red Alignment):
Adapted from the County of Maui’s Pali to Puamana Parkway 2005 coastal or makai concept.

A key element of this alternative is to maximize use of the existing Honoapiʻilani Highway right-of-way, particularly through Launiupoko and a portion of Olowalu.

Sea Level Rise Inundation Encroachment Area

  • will avoid approximately 84%
  • remain inside roughly 0.6 miles (3,330 ft)

ALTERNATIVE 2 (Yellow Alignment):
Adapted from the County of Maui’s Pali to Puamana Parkway 2005 “middle” concept.

Sea Level Rise Inundation Encroachment Area

  • will avoid approximately 71%
  • remain inside roughly 1.1 miles (6,000 ft)

ALTERNATIVE 3 (Green Alignment):
Adapted from the County of Maui’s Pali to Puamana Parkway 2005 “mauka” concept.

It is identical to Alternative 2, except in Olowalu where the alignment is further inland or mauka.

Sea Level Rise Inundation Encroachment Area

  • will avoid approximately 71%
  • remain inside roughly 1.1 miles (6,000 ft)

ALTERNATIVE 4 (Purple Alignment):
Also adapted from the County of Maui’s Pali to Puamana Parkway 2005 “mauka” concept.

The alignment for Alternative 4 was selected to realign the highway as much as possible away from the Sea Level Rise Inundation Encroachment Area, without as much consideration for property ownership as other Alternatives.

Sea Level Rise Inundation Encroachment Area

  • will avoid approximately 92%
  • remain inside roughly 0.3 miles (1,300 ft)

NO-BUILD (Existing Highway):
Reflects future conditions if the proposed project were not constructed.

Nature-based solutions, revetments and seawalls, or a combination of those protections combined with elevating the road are short- to mid-term fixes. They would be included due to the current state of the road and chronic impacts from coastal hazards.

About the Project

The project limits extend approximately 6-miles from the sandy beach strands of Pāpalaua Beach Park, near Manawaipueo Gulch, and continues through Ukumehame and Olowalu to the easternmost point of Lahaina Bypass in Launiupoko. 

Several recent reports prepared by the Hawaiʻi Department of Transportation (HDOT) document the natural hazards to which its facilities are exposed statewide:

These reports describe how vulnerable Hawaiʻi’s coastal belt roads are to seasonal ocean swells along with storm surges that cause shoreline erosion and damage. Honoapiʻilani Highway is no exception.

Segments of Honoapiʻilani Highway, particularly in the southern portion of West Maui (Ukumehame, Olowalu, and Launiopoko), are affected by multiple natural hazards including coastal erosion, annual high wave flooding, storm surge, and wildfires. In the Statewide Coastal Highway Program Report, the Olowalu and Ukumehame segments of Honoapiʻilani rank #2 and #12, on HDOT’s list of priority projects to address coastal erosion.

Service disruptions and suboptimal conditions such as high wave wash are regular occurrences on this low-lying highway. As the primary access to West Maui, when these road closures occur, they have significant impacts on the quality of life for residents and economy. 


For more than two decades, HDOT has been committed to addressing issues affecting the Honoapiʻilani Highway. In the 2000’s, with federal funding, HDOT attempted to realign and widen an 11-mile segment.

The project explored alternatives for increasing capacity, safety, and reliability while decreasing roadway congestion. The proposed project also sought to address the eroding shoreline between Maalaea and Launiupoko.

In 2007, the FHWA published a Notice of Intent (NOI) in the Federal Register to prepare an Environmental Impact Statement (EIS). However, an EIS was never completed due to limited funding.

While high costs and funding for long-term solutions placed them temporarily out of reach, HDOT continued to address the roadway’s reliability through short-term improvements. In 2011, HDOT constructed a seawall at Ukumehame during an emergency event, to keep the roadway from being washed away. 

In 2016, to secure other segments of Honoapiʻilani Highway, HDOT attempted to add additional revetments and seawalls along the Olowalu coastline. However, due to concerns from the Olowalu community regarding the impacts of seawalls on beaches and the aquatic environment, HDOT opted to implement the temporary solution of restriping and shifting traffic lanes inland within the existing right-of-way. 

Other plans recognize the need for long-term resiliency improvements include the Maui County's 2005 Pali to Puamana Parkway Master Plan as well as the recent West Maui Community Plan (Updated 2022), currently under review by the Maui County Council.

In addition to realignment, the County proposes to use the land makai of the realigned road between Pāpalaua Park and Puamana Park “as open space and park to buffer against the effects of sea level rise and climate change while providing recreational opportunities.” 

Submit a Comment

Please use the form to submit a general question or to comment on the Environmental Process.

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  • January 2023
    • Launch of environmental assessment process, which includes NOI and EISPN. 
    • 2023 - 2024: Environmental Planning Process
  • Early 2024
    • Draft Environmental Impact Statement Published
    • Public Hearing (February 2024)
    • 45-day Public Comment Process
  • Mid-Late 2024
    • Final Environmental Impact Statement Published
    • Preconstruction
  • 2025
    • Construction Begins
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