Manoa resident Bob Kern often gets startled awake at 2 or 3 a.m. when he hears the high-pitched buzz of illegally modified mopeds whizzing past his Wilder Avenue condominium. The noise of their engines, sounding like a swarm of angry bees, bounces off the densely populated buildings there.

“It’s really obnoxious because you know the person (driving couldn’t) care less,” Kern griped of the mopeds that zip by too fast and too furiously. “I think people feel really angry and they feel helpless” about the situation.

Late-night mopeds have also kept Amy Arkoff, who lives a few blocks away from Kern in Makiki, from getting a full night’s sleep for about the past three years, she said, and it’s taken a toll on her health and well-being.

Without that noise, “I’d be able to think; I’d be able to function. I’d be able to act like a normal person,” Arkoff said Friday. “Thousands of Honolulu residents have been unable to sleep through the night.”

Some Honolulu residents rely on mopeds as a cheaper alternative to owning a car in a dense city with one of the nation’s highest costs of living. How many mopeds currently operate on Oahu remains unknown because of the island’s one-time registration requirement.

But exasperated residents such as Kern and Arkoff say the noise created by certain rogue moped owners — those who soup up their rides with after-market carburetors and mufflers to exceed the state’s limits on speed and performance — is now out of hand. Searching “mopeds” in Oahu neighborhood board online records for the past several years indicates many others across the island agree.

“It’s reached a boiling point,” said Tim Streitz, a McCully-Moiliili Neighborhood Board member. “As the population grows and more mopeds come online, you have people living in higher urban densities where it’s affecting more people.”

Despite the growing concerns, state and local leaders have balked at passing legislation that would strengthen Hawaii’s existing laws against modified mopeds and curb the excessive noise. One lawmaker who regularly introduces those bills, Rep. Scott Nishimoto (D, McCully-Moiliili-Kapahulu), said he regularly sleeps with earplugs to block out moped noise.

The main noise culprits, according to one prominent moped dealer on Oahu, are the so-called “two-stroke” moped engines that the industry is phasing out.

Compared to newer four-stroke-engine mopeds that now dominate the market, those with the older two-stroke engines are louder, dirtier and guzzle more fuel — but they’re also coveted by a “subculture” of Hawaii moped enthusiasts because they can perform dramatically better (and even louder) when modified, said Akihiro Murakoshi, owner of Honolulu-based moped retailer Mr. Scooters Hawaii and repair shop Moped Doctors Inc.

Any new inspection programs on Oahu should target the two-stroke models in particular, Murakoshi said. His stores, which sell 600 to 800 mopeds a year, don’t offer two-stroke-engine mopeds and his repair shop refuses to repair any such mopeds that have been modified, he added.

Mopeds in Hawaii can’t have more than a two-horsepower engine or exceed 30 mph on a flat surface under state law. Souped-up mopeds provide their owners with the performance of a faster vehicle without having to pay the same insurance and registration requirements, both anti-noise advocates and dealers say.

Hawaii and Maui counties subject their mopeds to regular safety inspections but Honolulu and Kauai counties don’t, according to officials. In the past 10 years, Nishimoto and other state legislators submitted 33 bills targeting Oahu’s noise problem via registration and inspection programs, as well as stiffer penalties for violators.

Only 18 of those bills managed to get at least one hearing and none passed, according to research by legislative staff.

This year’s legislative session could get results, however. In the past year or so, Oahu’s neighborhood boards have seen a groundswell of organizing to finally get something passed.

Nine of Oahu’s 36 neighborhood boards so far have passed a resolution urging city and state lawmakers to enact laws to reduce excessive moped noise, according to Streitz. Last year, he was chairman of a special group to look into the noise issue and potential solutions.

Now he’s helping to lead Honolulu’s new Moped Noise Mitigation Working Group, made up of several neighborhood board members and concerned citizens.

The state House and Senate each has a bill advancing that could establish more moped regulations. But even supporters of the bills are wary of pushing those regulations too far, making it too costly and cumbersome for a mode of transportation that’s supposed to be cheap and easy.

Honolulu officials currently require a one-time moped registration fee of $15 — the same as for a new bicycle. House Bill 1753 currently proposes an annual $50 moped registration fee — a price that both Streitz and local moped dealers on the island say would be too high.

“We’re not trying to take mopeds out of use, just the bad ones,” said George West, chairman of the Diamond Head/Kapahulu/St. Louis Heights Neighborhood Board.

Meanwhile, Honolulu police say they have a hard time enforcing the state laws against modifying mopeds. Even if the modified vehicles are louder than they were originally, such noise levels on the street can be “subjective,” making it hard to bust a moped owner who’s made the changes, police say.

“It’s not illegal to own a loud muffler … (and) it goes back to what’s loud. That’s the problem we have,” Honolulu Police Department Maj. Darren Izumo told the City Council earlier this month, as its members considered their own moped inspection ordinance. “Some (mopeds) are silly — it’s obviously modified. But other than that, how can you tell?” The Council deferred to see what measure the state might pass this year.

HPD’s Traffic Division reported issuing eight citations for modified moped engines in 2015.

Streitz and other activists say that an inspection program could solve the police’s enforcement challenges. The right program could allow police to send mopeds that they suspect of being modified back for a new inspection, they said. Then, if the moped gets stopped on the street again and it hasn’t been reinspected, the owner could face a fine.

HPD has further stated that an owner could easily remove and reinstall the modified engine parts to pass an inspection. That frustrates Streitz, West and other reform advocates, who say inspections would still make a dent in the noise problem even if it doesn’t stop everyone.

At a state hearing on HB 1753 Friday, Arkoff maintained HPD has “abdicated its responsibility” on moped enforcement because it hasn’t cited more of the illegal vehicles.

The city’s Customer Services Department reports having registered nearly 39,000 mopeds between 1979, when those one-time registrations started, and 2015. That includes more than 11,000 in the past five years. The city doesn’t know how many are on the roads today since those owners don’t have to re-register.

“We can’t sit here and do nothing when every neighborhood board, I think, is passing resolutions asking us to do something,” Honolulu City Councilwoman Ann Kobayashi said at a Council meeting earlier this month. “We have to try, and maybe it’ll work. If it doesn’t we’ll keep trying. … We need to find a solution for this.”