Kakaako’s relatively sleepy Halekauwila Street between South and Keawe streets will transform into a bustling bus and rail transit hub when the Civic Center rail station is scheduled for revenue service in 2031.

The Sept. 30 approval by the Federal Transit Administration to end the city’s rail line in Kakaako means the number of rail passengers will nearly quadruple in Kakaako — from the original forecast of 3,250 to 12,870 per day. The additional riders represent a difference of 296% from the previous rail plan to end the system two stations farther at Ala Moana Center.

The two-story Civic Center station near the city’s Mother Waldron Neighborhood Park will be built on the makai side of Halekauwila Street, where two lanes of existing metered street parking likely will be eliminated to have enough room for the station.

Halekauwila also will be used by a fleet of buses awaiting rail passengers.

During peak morning commute hours, between 6 a.m. and 9 a.m., the Honolulu Authority for Rapid Transportation expects Kakaako rail passengers to overwhelmingly rely on bus service. These passengers arriving at and departing from Civic Center will be relying on bus routes that do not yet exist.

In the peak morning period, only 16% of rail riders are expected to walk to and from the station, with most of the balance relying on TheBus, according to HART.

HART estimates 80% of passengers arriving by rail would continue eastward by bus during the morning peak. “Conversely, an estimated 84% of the westbound rail passengers would arrive at the station via bus during the morning peak. … (There) will be almost three times as many riders in the eastbound direction than in the westbound direction during the morning peak period. This also illustrates the importance of the rail system in bringing commuters into town from the west side of the island.”

How many buses will be needed in the morning and throughout the rest of the day remains unclear, said Jon Nouchi, deputy director for the city’s Department of Transportation Service, which runs TheBus system and will operate the rail system once it opens for paid passenger service.

Two-lane Halekauwila Street has the capacity for four lanes of traffic between South and Keawe streets.

So two lanes of existing metered street parking likely will be eliminated to allow for both east- and west-bound bus traffic, none of which currently exist along Halekauwila, Nouchi said.

“Parking is going to give way to transit,” Nouchi said. “It’s preliminary thinking.”

Any number of the details still need to be worked out.

But some buses likely will be dedicated to taking passengers to the University of Hawaii, others to Waikiki and additional buses heading mauka on South Street to the Alapai bus Transit Center on South King Street about a half-mile away, along with destinations at the Frank F. Fasi Municipal Building and state Capitol.

Fronting the Civic Center station, Halekauwila Street could end up resembling a bus-only area like downtown’s Hotel Street in front of District Court, Nouchi said.

The buses used for Civic Center rail passengers likely will be larger “articulated” electric buses that are both quiet and produce zero emissions — but are not yet part of TheBus fleet, he said.

The city currently runs 17 smaller electric buses out of 466 total buses, which are scheduled to grow to 480 next month.

Nouchi calls the city’s electric buses “quiet ghosts.”

Kim Coco Iwamoto, treasurer of the Ala Moana-­Kakaako Neighborhood Board, said it’s difficult to assess the impact of thousands of daily rail passengers and an unknown number of buses with so few details.

“It feels like we haven’t had enough of a presentation to know what’s going to happen,” she said. “No one’s been explicit in order to critique it in any way.”

With UH students and Waikiki workers possibly arriving to and departing from Kakaako at different times, it could turn out that Kakaako experiences a “rolling rush hour,” Iwamoto said. “But it’s still a lot of bodies moving in and out of very narrow lanes. I don’t know how all of these buses are going to wind through these areas.”

The previous plan was to end rail service at Ala Moana Center, Hawaii’s largest transit hub, at a cost of $11.1 billion and a deficit of $1.3 billion. While that plan left the city cash-strapped, HART officials insist that under the new plan they will have enough money to stay in the black. The plan includes eliminating two stations from the original vision for a 20.2-mile, 21-station route and ending service on Halekauwila.

The 18.75-mile, 19-station project is now scheduled to be completed in May 2024 at a cost of $9.8 billion.

Roger Morton — the head of DTS and a HART board member — said on Sept. 30 that “although it will be challenging we’re going to make Civic Center work” through “very easy connections.”

After the morning peak hours in Kakaako, HART estimates rail passengers will be less reliant on TheBus and more will then walk or ride bicycles.

In Kakaako, HART said, about 32% of the passengers are destined for the downtown Honolulu or Kakaako areas, and would mostly continue via walking or biking. About 19% of the passengers are bound for either the Ala Moana or Moiliili area. About 19% would continue to UH Manoa, while about 30% would continue to Waikiki or beyond (including Kaimuki and East Honolulu). About 46% of the eastbound rail passengers who get off at the Civic Center station are going to destinations beyond Ala Moana, and these passengers would need to transfer to a connecting bus, regardless of where the transfer point is.