DANVILLE -- Some call it "the Khyber Pass of Danville" -- a narrow, winding stretch of Diablo Road with hazards from commuters rushing to work and school and a growing number of bicyclists pedaling to Mount Diablo for exercise.
The solution: Get Danville to widen a 1.7-mile-long stretch of road and add bike lanes there, say some residents, cyclists and leaders of the nearby community of Diablo.
The suggestion, however, is getting a cool response from town planners who worry about the steep financial and environmental cost.
Widening the road would require grading large chunks of hillside, chopping down more than 150 trees, relocating a creek and changing the bucolic nature of the road lined by oak and eucalyptus trees, Danville planners say.
The Danville Town Council will hear both sides of the debate Tuesday night in a public hearing before a possible vote on plans for the 66-house Summerhill development south of Diablo Road.
Road-widening advocates said Danville should make Summerhill help pay for a wider road with bike lanes because traffic from the proposed new homes will worsen traffic and safety problems.
"It is a dangerous road for cyclists and motorists, and Danville needs to step up to the plate and make it safe," said Jeff Mini, a Diablo resident. "This is the gateway to Mount Diablo, yet I can't think of a more dangerous road."
Danville cyclist Clelan Tanner called the stretch of road "the Khyber Pass of Danville" because it's in a gap in the hills, and traveling it means "taking your life in your hands."
The agency in charge of Diablo roads and police also has urged the Town Council to make Summerhill contribute money for bike paths on Diablo Road from Green Valley Road to Mount Diablo Scenic Boulevard, the route to Mt. Diablo State Park.
In a Wednesday letter to Danville leaders, the Diablo Community Services District said it is considering barring nonresidents from pedaling through Diablo's private roads as a detour to reach Mount Diablo while avoiding dangerous Diablo Road.
Some cyclists blow through stop signs, talk loudly and risk collisions with pedestrians on narrow Diablo streets in the affluent community, residents say.
Some residents and cyclists suggested that Danville and the county jointly contribute to the road widening because they share responsibility for different parts of Diablo Road.
But getting Summerhill to pay something is a start, road-widening advocates said.
Danville planners don't see it that way. They said it would be unfair to stick Summerhill with road-widening costs when the 66 proposed homes would generate only a small percent of the traffic on the road used by many drivers from Danville, Diablo and Blackhawk.
The developers already have agreed to offset even more than their share of traffic impacts, said Kevin Gailey, Danville's chief of planning.
To reduce long traffic backups, the builder has agreed to lengthen a westbound lane on Diablo Road at its intersection with Green Valley Road.
The developer also has agreed to provide a right of way for a new off-road trail south of Diablo Road, giving pedestrians and cyclists a partial bypass to avoid the most dangerous stretch of the road.
Many bicyclists, however, said the off-road trail would offer little safety relief because fast-moving cyclists won't want to ride on the same path with joggers, walkers, dog walkers and babies in strollers.
Contra Costa County Supervisor Candace Anderson, a former Danville mayor, said widening Diablo Road to add bike lanes would be the best long-term solution, but she doubts the city and county can afford it anytime soon.
While bike lane advocates say the town and county both can get state, federal, regional and local grants to promote safe bicycle and pedestrian travel, Anderson said she doubts there would be enough for widening Diablo Road.
Anderson agreed the safety headaches could have been avoided if the Board of Supervisors in the 1970s had required developers of the Blackhawk community to pay to widen the stretch of Diablo Road to offset traffic from the thousands of residents there.
Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff.
WHO: Danville Town Council
WHAT: Public hearing and possible vote on plans for 66-house Summerhill development project south of Diablo Road. Some speakers will ask Danville to require the developer to help pay to widen Diablo Road and add bike lanes there.
WHEN: 7:30 p.m. Tuesday
WHERE: Danville Community Center, 420 Front St.