The state opens a new segment of the Diamond Head summit trail today, the latest phase in a long-term improvement project aimed at preserving and upgrading one of Oahu’s most visited scenic spots.

Hikers who reach the steep "99 Steps" stairway near the top will be detoured, for now, to the left onto a new footpath and stairway. When all repairs are completed in December, the new 450-foot segment will be part of a one-way loop trail designed to ease congestion at the top.

"People are loving the trail to death, so we’ve had to put a lot of work into it," said Yara Lamadrid-Rose, Diamond Head State Monument coordinator. More than 660,000 people visited the park in the fiscal year that ended June 30, making it the fourth most visited Hawaii state park (Nuuanu Pali State Wayside is No. 1), the state said.

The new segment, which cost $1.1 million, is part of a counterclockwise loop trail at the summit that will address several bottlenecks, including the 99 Steps and an 18-inch-wide ledge that forms part of the path near the top. Until now, hikers had to squeeze past each other or take turns negotiating those sections.

With the new setup, hikers will go up the 99 Steps and to the summit platform in the usual way, but descend on the new trail segment.

For the next two months, however, the new trail segment will be the only way to the top as workers widen the 18-inch-wide ledge to an average of 3 feet wide, a $500,000 job. The 99 Steps will remain open to people as an exercise area, but access to the top will not be available on that path during the construction period.

"To me part of the fun is going up those stairs," Daniel Quinn, director of state parks, said at the park Wednesday.

Trail improvements are expected to be completed sometime in mid-December. Until then, hikers will take the detour to summit and park users will be shooed out at 3 p.m. on weekdays while crews airlift materials by helicopter.

"Slowly but surely we’ve been making improvements, and I’m sure everyone would like to see it faster, but you know, you work with what you’ve got," Lamadrid-Rose said.

Diamond Head has been enjoyed by tourists and residents alike for its natural beauty and military history since it opened to the public in the late 1970s.

Visitors David and Pat Purdin of Ohio hiked to the summit Wednesday and enjoyed the view of Waikiki and East Honolulu. The Purdins are on a two-week vacation to celebrate their anniversary, and before the couple left Ohio, they said David Purdin’s brother told them, "Whatever you do, you have to climb to the top of there."

David Purdin joked Wednesday that he wanted to shoot his brother for sending him on a strenuous hike up a crater, but his wife, Pat, said, "It’s gorgeous."

Hawaii News Now video: New section of Diamond Head trail opens