Shared from the 3/6/2021 San Francisco Chronicle eEdition

Easing road rage

Turnouts on Mount Diablo cut bike-car collisions to near zero

Photos by Stephen Lam / The Chronicle

A truck passes cyclists going up Summit Road on Mount Diablo, which can be a dangerous maneuver.


Alan Kalin, president of Mount Diablo Cyclists club, stops at one of the turnouts on Summit Road that allow bicyclists to let cars pass them.

Photos by Stephen Lam / The Chronicle

Bicyclists climbing Mount Diablo ride by a turnout on Summit Road. State Parks officials say bike-car crashes are at near zero since the turnouts were installed.


Signs discourage motorists from passing bicycles on a blind curve on South Gate Road on Mount Diablo.

A model program designed to defuse tensions between cyclists and drivers on narrow back roads includes new bike turnouts at Mount Diablo that have reduced collisions to near zero and eased showdowns, California State Parks officials say.

For many cyclists, riding Summit Road to the top of 3,849-foot Mount Diablo is a benchmark event. An estimated 150,000 make the ride every year.

But the winding roads up the mountain, which rise from Walnut Creek and Danville to the summit, are also frequented by motorists heading up to score panoramic views of the Bay Area. Showdowns, shouting matches and tensions between the two groups have been going on for decades, with motorists stuck behind slow-going cyclists and cyclists incensed about close calls with passing cars. There have also been many collisions, but no fatalities.

“We know there’s knuckleheads on both sides, and they’d honk their horn, we’d yell and they’d be angry and pass dangerously,” said Alan Kalin, president of the Mount Diablo Cyclists, a club with 1,300 members.

An average of 23 bike-car collisions per year occurred on the roadway from 2010 to 2014 — more than 100 in five years — said Adeline Yee, State Parks information officer. Most accidents at Diablo occur at narrow uphill sections where cars pass slower bikes on blind curves by crossing into the oncoming lane and striking cyclists coming downhill from the other direction, she added.

To address the problem, State Parks and the cyclist group partnered on measures to reduce road rage and improve safety, starting in 2014 with a series of turnouts that allow cyclists to pull over and let drivers pass. Four new turnouts, constructed over the past year, opened recently, bringing the total in the park to 17. These are likely the only designated, signed and paved bike turnouts available on country roads anywhere in California, Kalin and others believe.

The results are promising. In the past two years, only one bike-car collision has been recorded on Summit Road, Yee said.

“It’s ridiculous to think you’re going to follow a bike rider going up the mountain at 3 mph for 11 miles,” said Bruce Erickson, a volunteer park aide for 10 years who drives to the top of Diablo more than 15 times per month. “The turnouts are a blessing for drivers.”

Mount Diablo towers over Diablo Valley and the Interstate 680 corridor. Many riders travel a 26-mile round trip to the summit, starting in downtown Walnut Creek.

With the safety improvements, the decline in accidents has occurred with an increase in visitation during the pandemic, Yee said. Visitation to state parks, including Mount Diablo, “has been higher than usual” during the past year, she said.

While total visitors is tough to gauge, in a five-day snapshot last fall, a motion-activated camera at Mount Diablo recorded that about 60% of the traffic there was cyclists and 40% automobiles, according to numbers verified by Mount Diablo Cyclists.

Most of the back roads in the Bay Area were constructed in the 1930s with lanes often just 8 to 9 feet wide. The hazards on Diablo are common on many back roads popular with cyclists.

On the Peninsula, sections of upper Page Mill Road, Tunitas Creek Road and Kings Mountain Road that connect to Skyline Boulevard are potential death traps for cyclists. In Marin, it’s the same at Sequoia Valley Road to the Panoramic Highway, Bolinas-Fairfax Road across the Marin Watershed and Pierce Ranch Road at Point Reyes National Seashore. In the East Bay, Grizzly Peak Boulevard above Oakland, Canyon Road in Moraga, Reliez Valley Road in Lafayette and others can also present nightmare moments.

Many of these roads could benefit from a similar program, Kalin said.

“This is not rocket science,” he said. “Bike turnouts are relatively inexpensive, and you can add them on any road. Especially on the steep hills, you (on a bike) are going so slow, you want to get over to the right, and let the cars go by.”

The turnouts at Diablo are part of a long-term program to improve road safety and lower cycling accidents. State Parks added double-yellow, no-passing lines on 17 miles of roads in the park and painted “sharrows” — notices and lines to remind drivers and cyclists to share the road — every half mile on uphill lanes. Signs posted on the route advise cars not to pass bikes on blind curves and caution cyclists heading downhill to slow down to avoid crashing.

Each bike turnout costs roughly $15,000 to $20,000, depending on its size, according to State Parks. Kalin has worked with the agency to identify where more turnouts could be constructed. He acknowledges the limitations of the State Parks budget, and said he is looking at foundations for grants.

The turnouts have largely ended the road rage between drivers and cyclists, Kalin said. As long as cyclists don’t stack two and three across and block a lane, most drivers have accepted it to give cyclists some room, according to rangers.

“When we pull off on a turnout, the drivers smile and wave at us as they pass,” Kalin said. “It’s so much safer and the animosity between motorists and cyclists has dropped dramatically. I’ve watched it. It’s working.”

Tom Stienstra is The Chronicle’s outdoor writer emeritus. Email: Twitter: @StienstraTom

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