It's been a highly contentious roadway for more than a decade, with everyone from motorists and bicyclists to pedestrians and residents of the surrounding Charleston-Arastradero corridor in Palo Alto at times seeing red.
But at a community workshop Tuesday evening about how the road could be made safer for bicyclists, several dozen residents saw a different color: green.
Green bike lanes are rapidly becoming part of Palo Alto's urban roadscape. The rubbery-looking surface marks out a defined bike lane that is hard to miss, even when in the middle of the road, as on Park Boulevard south of California Avenue, residents at the meeting said.
Although some residents said they think the green color is ugly, bicyclists said it is a vast safety improvement over traditional single white-line-striped bike lanes at the road edge or "sharrows" (arrows directing bikers and motorists to share the lane) stenciled with a bike symbol.
Most at the meeting agreed the city should improve Arastradero Road with additions that would change human behavior -- whether to slow traffic, make motorists more mindful of pedestrians or reduce student bicyclists' urges to travel in packs instead of single file.
Parent Jessica Rothberg has seen how green bike lanes alter how people act. With her teenage daughter behind the wheel, Rothberg watched in horror as three girls precariously rode their bikes three abreast across El Camino around a pork-chop-shaped cement island in the road.
Common teen etiquette would not leave one girl behind when riding in odd numbers, she said. But when the girls approached a green bike lane near El Camino Way, they switched to safer riding behavior. Two rode side by side and the third rode behind, all staying within the lane, she said.
Elizabeth Bonnet, another parent, also feels the green lanes are safer and more visible.
"It's so much more comfortable. I feel like the green lane is a safe place, like along Park Boulevard," she said. Stenciled sharrows are confusing, though, the parents agreed.
Transportation studies have found that green lanes shift a substantial percentage of bicyclists away from the "door zone," where they are often struck by opening car doors of parked cars. The changes in behavior were more pronounced than those found in studies of sharrows without the green pavement.
Green-lane experiments in Long Beach and Minneapolis documented corresponding decreases in auto-bicycle collision rates, according to a report by the City of Oakland.
Another road feature, green "bike boxes," enable cyclists to move from the right-hand bike lane to a painted green rectangle located directly in front of a vehicle at stop lights. The vividly marked space allows drivers to see the bike; cyclists can easily make left turns without entering the roadway from the driver's blind side, said Penny Ellson, traffic safety representative for Gunn High School.
The Charleston-Arastradero corridor serves 11 schools of all grades. The busy road is an east-west connector between U.S. Highway 101 and Interstate 280. It is the largest arterial in the city's south, serving multiple modes of transportation, from buses and cars to bikes and pedestrians, Ellson said.
And it is a dangerous stretch of roadway for ever-increasing student traffic. At Gunn High School alone, 871 students rode their bikes to school during peak hours, according to an October 2013 count, she said. And more kids on bikes are expected to flock to school. Terman Middle School is adding about 200 new bike racks, she said.
"We've learned that when you build it, they come," Ellson said of the anticipated bike traffic.
The city's consultants and engineers are considering multiple roadway changes, including creating a "cycle track" that is separated from traffic by an island or curb. With streets, driveways, turning lanes, stop lights and lanes that narrow from four to two in places, however, the task is not as simple as adding green paint.
Ellson and others offered other suggestions Tuesday. For instance, a landscaped median island would slow traffic and raise awareness, Ellson said.
"Studies have shown that when you put objects close to peripheral vision, people start scanning for pedestrians, and when they do that, they release pressure from their gas pedals and slow down," she said.
Others suggested that existing "pork chop" islands at El Camino Real and Arastradero, which residents said obstruct the view for drivers and cause a squeeze for bicyclists who must compete with turning cars, be removed.
Jimmy Sims, project engineer for consultant Mark Thomas & Company, Inc., said the firm is currently working on aerial mapping and counting traffic.
Various plans will be presented to the public in August, with a review by the city boards in the fall.
A finalized plan will be developed by fall or winter 2015, followed by an environmental review.
A construction design is scheduled to be completed in winter 2016.
The plan will include left-turn refinements, bulb-out improvements, bike boxes, enhanced crosswalks, widened sidewalks and improved vehicle-traffic flow.
But the actual work could take until 2018 or beyond to complete, Holly Boyd, city senior engineer, said. The city has a $450,000 grant for work on Charleston Road between Alma Street and Middlefield Road; a $1 million grant would cover work on Arastradero between Gunn High School and Georgia Avenue. The remainder would not start until there is funding, she said.
That isn't necessarily a bad thing, considering the confusion and traffic snarls that have been the corridor's legacy in recent years.
"It would not be feasible to construct the entire corridor at one time. That would be a nightmare," she said.
More information and updates on the project are available at cityofpaloalto.org/cacorridor.