Portions of a state highway that snakes along the west coast of Maui are crumbling into the ocean and residents fear that a major storm could wash out the road — cutting off thousands of west-side residents and visitors from critical emergency services.

Over the years, the Hawaii Department of Transportation has implemented emergency stopgap measures, building seawalls along the shoreline, laying boulders and filling sandbags to try to keep the ocean at bay and the highway open.

But local scientists and city officials say those efforts have been inadequate, with waves often washing over Honoapiilani Highway during large swells. Making matters worse, they say the shoreline hardening is contributing to coral reef destruction and the loss of treasured beaches where locals surf and fish.

For years, Maui officials have urged the DOT to move the highway mauka of the coastline to preserve westside beaches and safeguard west-side residents’ access to the island’s only major hospital, Maui Memorial Medical Center, and the main airport in Kahului. The road that leads up to Lahaina, where many of the island’s resorts are located, is also the only route for emergency vehicles to get in and out of west Maui.

As of May 2015, DOT officials said that plans to relocate the highway, which have been discussed for at least 15 years, according to state documents, were still in the works.

But the department now says that relocating Honoapiilani Highway inland is one of dozens of major highway projects throughout the state that they are putting on hold for at least the next 20 years.

“This is more of a congestion project that would cost hundreds of millions of dollars — money that the state just does not have at this point in time,” DOT spokesman Tim Sakahara said of the Honoapiilani project.

State officials say they’ve shifted their funding priorities to maintenance projects, such as road repaving, and that they need more money to execute some of the more complicated projects, such as building new roads or expanding lanes. They asked for increases in the state’s gas tax, vehicle registration fee and weight tax earlier this year to bring in more revenue for the department, but the Legislature rejected the hikes.

Rep. Angus McKelvey (D, Lahaina- Kaanapali-Honokohau) said he felt the DOT was trying to strong-arm the Legislature into giving them their tax hikes.

“It seems to me, they didn’t get funding and by threatening big projects all these lawmakers are going to be pressured to pass this gas tax,” he said.

Meanwhile, the DOT plans to move forward on a new seawall and boulder revetment along Honoapiilani Highway, stoking anger among local residents.

“The road is falling into the ocean already, so it really is an emergency now because they have waited,” said Albert Perez, executive director of Maui Tomorrow Foundation, an environmental advocacy organization. “It is just unconscionable, in my opinion.”

DOT is moving ahead on the next phase of a bypass around Lahaina, a $38.6 million project that will stretch south to Olowalu and is expected to ease traffic congestion. This will help, but it won’t resolve the safety issues that plague a 6- to 8-mile stretch from Olowalu down to Papalaua Wayside Park, said Mariah Gill, an environmental consultant for West Maui Land Co., which owns land in the area.

She said that this stretch of highway is the most vulnerable to sea level rise and ongoing erosion. Waves and debris often wash over the road, she says, creating dangerous driving conditions.

“There are huge traffic issues,” Gill said. “It used to take 20 minutes from Maalaea to Lahaina. Now you can sit there for hours because people are slowing down to avoid waves crashing into the road or pulling off to go surfing. It is really bad. That stretch of road has actually been operating at failing level since at least 2012.”

Along some parts of the highway, the beach appears to almost blend into the asphalt. Earlier this month, an endangered Hawaiian monk seal could be seen sleeping about 6 feet away from speeding traffic.

Gill, who has a master’s degree from the Yale School of Forestry and Environmental Studies, has become an advocate for realigning the highway, poring through government documents and starting a website and Facebook page with information about the project.

While DOT last year had pegged the cost of the realignment project at between $600 million and $800 million, she said that relocating this smaller, critical stretch would likely be much less.

The area has three landowners — the state, county and West Maui Land, which supports the highway relocation.

The county purchased 100 acres in Ukumehame for $4 million in 2006 to prevent the area from being developed and to make it easier to move the highway, said Rod Antone, a spokesman for Maui Mayor Alan Arakawa, who has said that the project is a top priority.

Gill said that Maui residents can’t wait 20 more years to have the highway moved inland.

“The actual asphalt is crumbling into the ocean at this time. It is bad,” she said. “I really don’t know if we can act soon enough to prevent another seawall. We’ve known about this for 20 years.”

In 2001, high surf eroded 40 feet of the shoulder of the highway at Olowalu. To shore up the highway, DOT placed large boulders in the washed-out area and used river rocks to fill in holes between the boulders, according to documents from the state Department of Land and Natural Resources. Later, concrete barriers were placed along the highway’s shoulder.

State transportation officials had obtained emergency authorization to do the repairs, allowing them to bypass state and county permitting requirements.

In 2012 and 2013, DOT spent $13 million on building two concrete seawalls at Ukumehame and Launiupoko. Emergency proclamations issued by Gov. Neil Abercrombie allowed DOT to again bypass state and county environmental and cultural reviews.

Mark Deakos, a marine biologist and founder of the Hawaii Association for Marine Education and Research, said that sediment runoff from the seawall at Ukumehame severely damaged the offshore reef.

“The impacts that seawalls have on our coastlines and beaches and coral reefs have been known for decades, so when DOT moves forward with protecting infrastructure by building seawalls it raises the question, ‘Why are there no alternatives?’” he said. “We know it will increase erosion and we will lose beach access.”

DOT is now planning to move forward on another concrete seawall along about 1,200 feet of shoreline at Olowalu, according to county documents. The cost is estimated at between $20 million and $30 million. DOT is also planning a rock revetment along 900 feet of shoreline at an estimated cost of $2 million.