Local traffic safety advocates are ramping up a grass-roots effort to provide fluorescent flags for pedestrian use at some of Oahu’s most dangerous crosswalks.

On Thursday members of the nonprofit Hawaii Bicycling League delivered the latest batch of 30 bright orange-and-yellow flags to three un-signaled crosswalks along a dicey half-mile stretch of Kalanianaole Highway in East Honolulu as cars and trucks sped by — many of them above the 35 mph speed limit.

It’s the same area where, in June 2015, Dr. Cynthia Timtim Soneda went for a morning jog and, while possibly trying to avoid a nearby traffic accident, became that year’s 11th pedestrian fatality when a car struck her in one of those marked crosswalks.

“We’ve had to deal with this. We know how dangerous it is,” area resident Christine Langworthy said as she helped fasten the flags’ durable plastic containers to poles on both sides of the highway. “This is a first solution to this problem.”

Since May, flags have also been left at 25 un-signaled crosswalks along a 10-mile stretch of Farrington Highway from Nanakuli to Makaha, according to Hannah Neagle, a Bicycling League coordinator. It costs about $50 to leave flags at each crosswalk, and they’re funded through donations, Neagle said.

Waianae Coast groups and businesses started to maintain the flags after a suspected drunken driver struck and killed 19-year-old Kamehameha Schools football standout Kaulana Werner as he crossed Farrington Highway in April.

State Rep. Andria Tupola (R, Ewa Villages-Kalaeloa-Ko Olina- Nanakuli) says the flags have been working well and that the Leeward community hasn’t seen any pedestrian fatalities since they arrived at the crosswalks. Many of the flags have been stolen, however, and volunteers replaced 80 of them there Thursday, she said.

In 2013 the state Department of Transportation pulled similar flags from Pali Highway crossings, citing liability concerns. The DOT did not respond to a request for comment Thursday. Bicycling League Executive Director Chad Taniguchi said the state agency has approved the latest flag effort, led by his nonprofit group.

Taniguchi said the flags are a good first step toward better safety but not the final answer. Drivers need to change some habits, while local government needs to update traffic laws and install more traffic signals and cameras, he said.

On Thursday, Soneda’s friend Dr. Vincent Au helped Taniguchi, Neagle and Langworthy test out the flags on Kalanianaole Highway, waving them as they crossed in front of approaching cars.

“A seed is planted,” an emotional Au said later, reflecting on the effort to prevent more pedestrian deaths where his friend was killed. Using the flags, “cars stopped. Impressive. Wow.”

“And sometimes cars didn’t stop,” Au added.

There have been 17 pedestrian fatalities so far on Oahu in 2016, according to the Honolulu Police Department. The island had 19 total in 2015.