Federal highway officials are congratulating the state for reducing a long-standing backlog of federally funded highway projects by more than $100 million over the past year.

The Federal Highway Administration has warned the state that Hawaii could lose out on federal transportation funding unless the state processes its projects more quickly and reduces the backlog of unspent federal money.

The backlog, also known as the Pipeline, peaked in 2010 at $940 million in federally funded highway projects that were sitting on the books. The federal government had set aside money for those projects, but the state had not been able to move them forward and the money remained unspent.

The state reduced that backlog to $757.5 million by Sept. 30, 2014, and further reduced it over the past year to $656.5 million, according to an Oct. 2 letter from FHWA Hawaii Division Administrator Mayela Sosa.

“I commend you and your staff on the continued progress,” Sosa wrote in a letter to state Director of Transportation Ford Fuchigami. The progress made last year represents the largest single-year reduction in the backlogged Pipeline projects in the past five years, she wrote.

Sosa said the backlog is now the smallest it has been since federal fiscal year 2002. However, the state still has much to do to appease the federal government, which wants the backlog reduced to no more than $450 million over the next three years.

Gov. David Ige personally assured U.S. Transportation Secretary Anthony Foxx that Hawaii will do a better job of advancing transportation projects, and Ige said in a written statement he remains committed to clearing the backlog.

“We need the resources to fix our roadways, and this money needs to get into our economy as quickly as possible,” Ige said. “I’m pleased that the Highways Division is making sure that happens.”

After warning that the backlog had reached “unacceptable levels,” the U.S. Department of Transportation dispatched teams of experts to Hawaii last year to review the state systems used to approve, process and fund federal projects. The teams advised the state on how to fix problems with the system and warned that “decisive action must be taken to reduce the Pipeline.”

Hawaii receives about $160 million in new federal highway funding every year, and last year the Federal Highway Administration warned that Hawaii will be allowed just 180 days to move into actual construction from the time the federal government commits new funds for each new Hawaii highway project. In years past the state has often taken twice that long to begin construction on projects.

To meet the federal targets and spend federal funds more quickly, the state is now focusing more energy and money on relatively simple projects within existing rights of way, such as repaving roads, repairing guardrails and making safety improvements.

U.S. Sen Brian Schatz, D-Hawaii, said the state is making “very encouraging progress” but added that “we’re certainly not done.”

“We’ve been totally focused on maximizing federal funds, and this has been a real sore spot,” he said of the backlog. “We finally have some good news to report to Hawaii residents and taxpayers, that we are maximizing every penny. We have to be relentless, and we have to make sure that this fund balance doesn’t get out of control again.”