The city’s plan to pause rail construction at the civic center and shorten the Honolulu line by more than a mile would also reduce the number of people who will use rail each weekday by nearly 30% from the ridership projections of a decade ago, according to data from the Honolulu Authority for Rapid Transportation.

The original projected ridership of 119,600 boardings per day in 2030 would decline to about 84,000 if the rail line is shortened, according to the newly released proposed HART recovery plan, which means the scaled-down project would take fewer cars off of Oahu’s congested roads and freeways.

Honolulu Mayor Rick Blangiardi publicly proposed last December that the city shorten the rail line, which was originally supposed to extend from East Kapolei to Ala Moana Center. Blangiardi said the city doesn’t have enough money to reach Ala Moana Center, and proposed that construction be deferred for two rail stations and the eastern end of the elevated rail line.

The new recovery plan released by HART on Friday proposes to shorten the rail line by 1.25 miles, stopping construction at least temporarily at the planned Civic Center Station at the corner of Halekauwila Street and South Street. That is about a block from Waterfront Plaza and the Circuit Court building.

The recovery plan also proposes to defer construction of the planned 1,600-stall Pearl Highlands parking garage, which was supposed to offer a convenient place for rail riders from Central Oahu to park their cars before boarding the rail line to head into town.

But those changes would significantly affect ridership, according to the new recovery plan.

The city’s Full Funding Grant Agreement with the Federal Transit Administration in 2012 — which assumed a 20-mile rail line would be built all the way to Ala Moana — projected the rail system would have 119,600 weekday boardings in 2030.

However, a long series of cost overruns and other problems caused years of delays, and bus ridership in Honolulu has been slipping in recent years. That has raised questions about whether the old ridership numbers were still accurate, and HART CEO Lori Kahikina acknowledged nearly a year ago the rail ridership projections had declined.

Kahikina did not say at the time how much the ridership projections had dropped, but in late January HART told federal officials it had reduced its ridership projection for the full 20-mile rail line down to 100,600 average weekday boardings in 2030. That amounts to a reduction of nearly 16% from the original 2012 estimate.

Now the latest recovery plan for rail reduces the projected average daily ridership even further for the truncated line. The new ridership estimate of 84,000 in the recovery plan for the shortened line is nearly 30% lower than the original 2012 ridership estimate for the 20-mile line to Ala Moana.

“I suspect the 30% predicted decline is understated,” Roth said in a written statement, but added that he doubted the accuracy of even the original 2012 projections. “In short, I don’t think their ability to predict ridership is any better than their ability to predict costs.”

When the city signed a Full Funding Grant Agreement with the FTA in 2012, the rail project was budgeted at about $5.2 billion for the full 21 stations and 20-mile elevated line from East Kapolei to Ala Moana.

The latest cost projection in the new rail recovery plan is that even the shortened rail line from Kapolei to the civic center will cost $9.93 billion, including financing costs. According to the recovery plan, 83% of that expense will be borne by tourists and local taxpayers, while 17% will be picked up by the federal government.

HART spokesman Joey Manahan did not respond to a request for comment Sunday on the new ridership projections.