Waiaka Bridge Replacement

Kawaihae Road, Replacement of Waiaka Bridge and Realignment of Approaches
South Kohala, Island of Hawaii, State of Hawaii
Project No. 19D-01-19

Project Information

The State of Hawaii Department of Transportation (HDOT), Highways Division, is proposing to replace Waiaka Bridge and realign the roadway approaches to the Kawaihae Road and Kohala Mountain Road intersection. The project is located near Waimea in the South Kohala district on the Island of Hawaii. Waiaka Bridge is located along Kawaihae Road at mile post 58.88 near this intersection.

Project Purpose and Need

The existing Waiaka Bridge was built in 1932, and the purpose of this project is to bring the bridge up to current standards for roadway width, load capacity, bridge railings, and bicycle and pedestrian access. This bridge provides system connectivity for the surrounding communities and accessibility for modal inter-relationships, as it is a main linkage between a major shipping port on the western side of the Island of Hawaii and the rest of the island.

Waiaka Bridge is inspected every two years, and these inspections show that the existing bridge is structurally sound but eligible for replacement. The proposed project will provide a replacement Waiaka Bridge in conformance with American Association of State Highway and Transportation Officials (AASHTO) design requirements.

This proposed replacement of Waiaka Bridge effort to meet Federal and State design guidelines also presents an opportunity for HDOT to improve the alignment of roadway approaches to the bridge and traffic operations for the nearby intersection of Kawaihae Road with Kohala Mountain Road. Realignment of the existing approaches to this intersection will improve operations by increasing line-of-sight distances.

The current configuration of the Kawaihae Road / Kohala Mountain Road intersection can be confusing to motorists. The proposed realigned intersection will provide clearer directions, contributing to improved safety and traffic operations. The proposed T-intersection configuration would improve traffic operations by separating the eastbound left turns from the left turning vehicles, which would reduce delay for all users. The proposed roundabout configuration will reduce the stop-and-go nature of the existing T-intersection, and improve operations to a continuous traffic flow. The roundabout configuration will also improve safety by reducing the severity of crash occurrences from “broad side” to “angled type” crashes.

Project Environment Considerations

The proposed project will require some disruptions to the surrounding area, including lane closures, elevated noise levels, and potential air quality concerns due to dust generated by ground disturbing activities. The project team is committed to minimizing these impacts to the extent possible, including implementing the following measures:

  • Provide temporary access during construction for those travelling through the area.
  • Minimize any environmental impacts to the maximum extent possible; use of Best Management Practices (BMPs) will be implemented and coordinated with appropriate agencies.
  • Minimize acquisition of privately-owned lands.
  • Minimize project construction cost.

Build Alternatives for Bridge Replacement and Intersection Improvements

HDOT is evaluating two primary Build Alternatives for a replacement bridge with reconfigured alignments for the Kawaihae Road / Kohala Mountain Road intersection. One option is a replacement bridge with T-intersection, while the other option is a replacement bridge with roundabout. The Build Alternatives are shown below.

Replacement Bridge with T-Intersection
Replacement Bridge with Roundabout

Public Input and Project Schedule

The Draft Environmental Assessment is anticipated to be published in the December 2021, and there will be a public comment period associated with its publication. The Final Environmental Assessment is anticipated to be published in the Summer of 2022. The proposed project is scheduled to be advertised for construction in the Summer of 2023.

For more information, please contact:
Mr. Andrew Hirano
HDOT Project Manager
(808) 692-7546
[email protected]