King County abruptly halted a $75,000 project to install rumble strips along Vashon Highway last week after a group of cyclists — concerned the grooves and ridges will make bike-riding more hazardous — organized a hasty but spirited protest.

County officials said the state-funded project, which began last week and is about half-way complete, will not resume until they’ve had time to talk to Vashon cyclists and address their concerns. They hope to hold an open house on Vashon in mid-May.

“We want to make sure the community knows what the project entails, why we’re doing it and hear from them,” said Rochelle Ogershok, a spokeswoman for the county’s Department of Transportation. “We’re making plans to have a conversation with folks.”

Cyclists quickly rallied last week as news of the highway project — the installation of rumble strips down the center of Vashon Highway and along most of its shoulders — spread through their large but loose-knit community. Emails flew. Several called top-ranking county officials. And by Friday morning, a handful of cyclists stood on the corner of Vashon Highway and 204th Avenue S.W., where workers were about to resume their day’s work and Islanders were ready to engage in civil disobedience to block it.

“I’m prepared to park my car in front of them,” said Steve Abel, a high-profile Islander and avid cyclist, nodding toward his red Volvo. “We want to gain enough time for the politicians to realize what a screw-up this is.”

The cyclists said they had no objection to rumble strips down the center of the highway. But such strips along the sides of the road cut into the shoulders where cyclists ride, compromising the quality of their experience, forcing some cyclists to ride in traffic and making bike-riding on Vashon more dangerous, they said.

“It’s just totally impossible to ride on it,” said Rusty Knowler, who stood at the corner with his bike and who had just attempted navigating the indentations. “If there’s debris or a car parked in the way, you have to cross those strips.”

“They’re seriously damaging the best cycling in all of King County,” said Abel.

As the cyclists were contemplating their next moves, however, two King County Sheriff’s deputies showed up and told Abel and the other men that it was illegal to block the project. Sounding frustrated, Abel told the officers the project had to be stopped before more work was undertaken.

“The damage is being done to the roads today,” he said. “I rode yesterday, and it just about knocked me off my bike.”

But when the officers made it clear that blocking the project would result in arrests, Abel, who joked that he hadn’t been involved in civil disobedience since 1969, decided to instead head home and continue his telephone and email campaign. A few minutes later, a worker driving the large machine that grinds the pavement, creating the rumble strips, returned it to the corner. Asked what was going on, one worker said they had been told to stop the project for the day.

Abel, reached later at his home, said he had emailed County Executive Dow Constantine — whom he knows — Thursday night about the project. Shortly after he returned home Friday morning, he got a one-word email from the executive: “Suspended.”

“I feel good,” Abel said. “I feel it gives us a chance to talk about what is appropriate for Vashon Island.”

The county has been planning the project since 2010, when it received a $300,000 “high-risk rural road” grant from the state to install rumble strips along six separate spans of rural roads. Henry Perrin, a safety management engineer with the county roads division and a Vashon resident, said the county was able to get the funds after submitting a grant that showed the six county roadways had a high incident rate of what are called run-off-road collisions.

Between 2003 and 2008, for instance, Vashon Highway had about 15 run-off-road collisions a year, or 1.35 collisions per mile per year, he said.

Rumble strips have become an important tool in road safety, Perrin added. “They’re very effective and very inexpensive,” he said.

Perrin, himself a cyclist, said he and others contacted the region-wide Cascade Bicycle Club in advance of the project to discuss potential concerns. They learned from the club to install the rumble strips only along stretches of road where the shoulders are at least four feet wide, he said.

“If you’re on a four-foot-wide swath … and you’ve got this rumble strip, … I think that would make it quite a bit safer for cyclists,” Perrin said.

Some cyclists, however, disagree. The rumble strip cuts into the shoulder, forcing them to ride closer to the outer side of the road, where debris — branches, garbage and glass — tends to accumulate. Serious cyclists, they said, have learned to ride as close to the traffic lane as possible, where the pavement is generally clear of debris.

What’s more, they said, most accidents don’t occur from a cyclist getting hit from behind but from a driver pulling out of a road or driveway. Riders who hug the farthest edge of the road, meanwhile, are harder for drivers pulling out of roads or driveways to see.

Cyclists also note that federal and state standards suggest that rumble strips should be installed only on roads with speed limits of 45 mph or higher; most of Vashon Highway is 40 mph or less. They also said the county is failing to meet its own requirements for the project: Along at least 100 feet or so on the north end, rumble strips carved into the shoulder have resulted in a swath narrower than four feet.

The issue seems to have galvanized Vashon’s cycling community. By Friday, they had created a Facebook page, BikeVashon, with more than 70 people “liking” the page within two days. They now have a website, as well, called bikevashon.org, organized, the website said, to “fight a project to grind down our bike lanes this spring.”

A handful of cyclists held a meeting Saturday afternoon where they discussed their concerns and how to address them. The consensus, said Peter Ray, the group’s unofficial spokesman, is to push the county to regrade those stretches of highway that now have rumble strips along the shoulder.

It’s an expensive proposition, he said. According to one website, the installation of rumble strips costs $500 to $3,000 per mile, while removing them costs around $13,000 a mile. Even so, he said, many cyclists would like to see the strips removed.

“This (project) has destroyed some pretty good bike lanes,” he said.

County Councilman Joe McDermott, meanwhile, said he’s troubled by the lack of outreach county officials undertook before embarking on the project. They sent out a brief news release about it 18 months ago and consulted with the Cascade Bicycle Club, but McDermott said no announcement was issued in recent weeks about the impending project, which proved disruptive to drivers as well.

“I’m concerned that the roads division of King County didn’t communicate with people on the Island before it did it. That’s clearly an omission on our part,” he said.

McDermott said he’s not made up his mind about the details of the project and the installation of rumble strips along the shoulder.

“I’m not saying the project is dead. But it’s important that we come out and listen to Islanders’ concerns … before we potentially go forward,” he said.

Asked if the remainder of the project could change as a result of conversations with Islanders, he answered, “Absolutely. Otherwise, it’s a pretty meaningless conversation.”