With little more than the whir of their wheels adding to the din of rush-hour traffic, dozens of cyclists took part Friday evening in a silent, somber ride through central Santa Rosa to call for a greater focus on road safety.

The two-mile ride along Mendocino Avenue to downtown was part memorial and part quiet protest — meant to highlight the number of bike riders who have been killed or seriously injured in recent months in collisions with vehicles on Sonoma County streets.

Relatives and friends of some of those cyclists participated in the 5:30 p.m. procession. They included the wife and siblings of Ruben Hernandez, a 37-year-old Modesto teacher who was killed Tuesday morning when a pickup made a left turn in front of him as he was descending Fountain Grove Parkway.

"I feel like it's the beginning of our grieving," said Veronica Gutierrez, Hernandez's sister, who joined relatives in coming to Santa Rosa from Modesto.

Hernandez's widow, Elizabeth, rode the route with a stem of bright pink flowers attached to the back of her bike.

"We're here to support and protect the future cyclists that come to this county," Gutierrez said to the crowd of riders — estimated at more than 200 — who began at the county government administrative center.

The event was organized by the Sonoma County Bicycle Coalition, whose leaders framed it as a moment to mourn the losses of the past months.

Since mid-May in Sonoma County, five riders have been killed — matching the five-year total stretching back to 2006 — and several others were seriously injured in collisions with vehicles. At least two of the drivers in those incidents face criminal charges.

Sonoma County Supervisor Mike McGuire, among several government leaders and cycling advocates who spoke at the start and end of the ride, called it a "summer of sorrow for cyclists."

The visible response to the tragedies came in the line of riders stretched out for more than a half-mile along Mendocino. Some wore plain clothes, commuting home from work. Many were in recreational gear.

They stopped and talked quietly at stoplights. The riders yielded to motorists, and motorists at other times gave way to riders.

"I drive a car, too," said Jeff Brown, a Santa Rosa cyclist who waved a passing car through a right-hand turn at Mendocino and Seventh Street.

Police motorcycle units kept watch over the procession, which arrived at Old Courthouse Square without incident.

"We're not out here to point fingers," said Sandra Lupien, outreach director for the bicycle coalition. "We just know that everybody can pay more attention. Everybody can do better to follow the rules of the road."

The driver who turned in front of Hernandez, Adam Bigham, 22, of Sebastopol, was on his way to a construction site. Police said Bigham was cooperative and said there were no indications he was driving under the influence or distracted by a cellphone. Prosecutors are awaiting completion of a police report before they determine whether or not to file charges.

In addition to Hernandez, the other cycling deaths in the county since May were:

August Bissiri, 85, of Laguna Woods Village who was hit by a car and killed May 24 on Highway 1 near Bodega Bay.

David Standley, 34, who died May 31 when he apparently rode a bike into oncoming traffic on River Road.

Brian Laurie, 68, of Sonoma who died June 21 when he rode into the path of a big rig in Sonoma.

Retired Sonoma State University professor Steve Norwick, 68, who was fatally injured when struck from behind June 8 on Petaluma Hill Road.

The driver suspected to have struck Norwick, Robert Cowart, 68, of Rohnert Park faces felony hit-and-run charges and could face vehicular manslaughter charges.

A July 8 memorial ride out of Rohnert Park drew about 200 riders, including Norwick's friends, family and former students.

Vin Hoagland, a friend and colleague of Norwick's who attended that ride, also took part in Friday's event. The veteran cyclist said the rally was an important message of perseverance and support for a community that has been shaken.

"It's just so important for us to keep riding," Hoagland said.

You can reach Staff Writer Brett Wilkison at 521-5295 or brett.wilkison@pressdemocrat.com.