As thousands of bicyclists hit Bay Area streets for Thursday’s 18th annual Bike to Work Day, an increasing number will ride in a bike lane sure to grab the eye of even the most distracted driver.

Bright green bike lanes — really bright green — are spreading throughout the region to make bicyclists more visible and to ensure safety where cyclists are most likely to mix with heavy auto traffic.

“Let me tell you — it’s a bright day-glow green and even appears to have sparkles in it,” said Martha Bryan, of San Jose, after driving along Stevens Creek Boulevard in Santa Clara, where green lanes are being installed. “Man, is it ever visible.”

The idea of painted bike lanes has been around for a decade. Sunnyvale installed blue lanes on Moffett Park Drive about 10 years ago before state rules made green the color of choice because that color stands out more than lanes in blue.

But only recently has a growing number of cities embraced the colorized lanes. San Francisco installed them along Fell and Market streets in 2010, and San Jose this year will put in green lanes for the first time along busy San Fernando Street. Pleasanton, Oakland, Berkeley, Palo Alto and San Mateo either have them or are installing more.

“The public reaction has been overwhelmingly positive,” said Bond Yee, San Francisco’s Sustainable Streets director. “We hope that cyclists will begin to associate green facilities with useful, comfortable and popular bicycle routes.”

Changes up north

Bicycling-crazy Portland, Ore., has colorized bike lanes at numerous locations and concluded that such improvements lead to better driver behavior and make bicyclists feel safer.

A report found that 92 percent of motorists now yield to bicyclists compared with 72 percent before. And, perhaps more significantly, 87 percent of drivers now slow down compared with 71 percent before.

Since San Francisco installed green lanes on Fell Street, there has been a 40 percent reduction in the number of cars that block the bike lane as they try to enter the Arco gas station at Divisadero Street, according to a city traffic study. The station is known for having cheap gas.

When cars do block that lane, cyclists often are forced to veer into traffic along the busy three-lane, one-way street.

Santa Clara tested green lanes on Monroe and Scott streets before approving the Stevens Creek job.

“We noticed that motorists making the right turn from southbound Scott to westbound Monroe tended to drive in the bicycle lane (too soon), but after installation, that behavior was completely eliminated,” said city traffic engineer Dennis Ng.

While the number of bicycle deaths in California has remained flat for the past two reported years, injuries have increased 4.6 percent. The biggest danger often is at intersections near freeways, schools and shopping areas.

Green paint is also being used to outline what are called “bike boxes” in an attempt to eliminate right-hook crashes. Those occur when a driver races ahead of a bicyclist and at the last moment suddenly veers into the bike lane to turn right.

This puts a bicyclist who has the right of way at great risk of slamming into the side or rear of the turning car and is a leading cause of bicycling deaths when a vehicle is involved.

At red lights, only bicyclists can stop in the boxes. Vehicles must line up behind them. When the boxes are green, more seem to know the rules.

While the number of cyclists at the Portland intersections increased 32 percent, conflicts between motorists and bike riders decreased by about 31 percent after boxes were installed.

That has bike advocates pushing for more green lanes and bike boxes. If bicyclists feel safer, more people may get out of their cars to either commute or just go for a ride.

A few bumps in road

“That newfound sense of comfort can persuade people to get off of four wheels and onto two,” said San Jose Councilman Sam Liccardo, who often bikes to work and meetings around the South Bay. “Studies show that the mere presence of more cyclists on the street begets safer outcomes, as motorists gain awareness of the need to maintain a safe distance and speed.”

There have been some glitches. When a San Francisco motorcycle cop lost control and skidded on the green paint along Fell Street on a rainy day, crews had to return and recoat the thermoplastic material to make the lanes less slick.

The city now uses a granular sand mix with the paint. Others, including Palo Alto, use only an anti-skid thermoplastic material.

So far, most applaud the new look.

“I sure hope the people who make the decisions decide to use this same paint on the bike lanes throughout the county,” said Bryan, the San Jose motorist. “It might help some drivers to stay out of the lane and give the cyclists more visibility.”

That’s the idea.

Contact Gary Richards at 408-920-5335.