AASHTO Journal

Hawaii DOT Opens Last Phases of DKI Highway, Island’s Most Direct East-West Route

The Hawaii Department of Transportation, along with Gov. David Ige and the Federal Highway Administration, celebrated completion Oct. 10 of a major project to modernize and add capacity to the east-west Daniel K. Inouye Highway on the island of Hawaii.

That highway, which is also State Route 200 and was previously known as Saddle Road, was initially built as a one-lane road by the U.S. Army in 1942 to connect military training facilities, and named for its route through the "saddle" between the Mauna Loa and Mauna Kea volcanoes. It begins on the east at the outskirts of Hilo near milepost 6 and extends westward to Mamalahoa Highway or SR 190.

capitol0816.jpgThe Hawaii Legislature in 2013 voted to rename the upgraded section for former U.S. Sen. Inouye.

The last of the improvement projects connected the existing highway near milepost 11 to the west end of the Puainako Street extension, HDOT said.

At a cost of $57 million, it covered nearly six miles, rebuilt three miles of the existing highway to modern design standards with such safety features such as 8-foot shoulders, straighter alignment and a climbing lane, and added three miles of new road. It increased the overall highway capacity and removed potential conflicts between military operations and public traffic.

Previous phases widened and aligned more than 41 miles of road. The total work on nearly 48 miles cost about $316.5 million, HDOT said, of which the Army contributed more than $100 million.

"The importance of the combined Saddle Road Improvement projects as a cross-island route cannot be overstated. It is a huge accomplishment," said Ige. "Sen. Inouye's vision when he initiated the Saddle Road Community Task Force in 1993 is an excellent example of government and the community working together to benefit generations to come."

HDOT said the joint project it undertook with the "presented unique challenges" such as varying subsurface conditions including volcanic ash, and the need to take precautionary measures for containment, treatment and placement of cleared timber to help prevent the spread of the Rapid Ohia Death fungus.

The department said the newly completed highway climbs nearly 5,500 feet from its eastern terminus to its midpoint. In addition, rainfall along the route ranges from 10 inches to 200 inches per year, "which posed an additional challenge for crews during construction," HDOT said.

Questions regarding this article may be directed to editor@aashtojournal.org.

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