On our city streets, bicycles pedaled by human power and weighing a few pounds must maneuver among speeding cars, trucks and buses, so the city has introduced lane markings called sharrows, reminding drivers to share the streets with bikes.

The sharrows (shared lane pavement arrows) are indicated by a bike symbol and two directional arrows on the streets.

"Sharrows do not change the rules of the road for cyclists or drivers. They're just marks indicating to motorists to expect cyclists," said Gregg Hirakawa, spokesperson for the city's Department of Transportation.

Up to 6,000 people commute by bike in Seattle and that number is expected to triple in 10 years. The city plans to put in 53 miles of sharrows and 37 miles of bike lanes in the next two years.

Stone Way, just east of Ballard now has a sharrow. Later this year, sharrows will be introduced on 85th Street from 32nd Avenue to 8th Avenue.

Eighth Avenue, 100th Place and Third Avenue from 85th Street to 105th Street will have sharrows.

Capitol Hill, Magnolia, Fremont, West Seattle, Beacon Hill, University District, Stone way, Green Lake, Queen Anne, Central Area (Yesler Way), Rainier Beach and Georgetown are the other neighborhoods where sharrows will be placed.

The city did not begin the sharrows program because of the demands of bicycle advocates, said Hirakawa. "It was done by the city as a visual cue to enhance existing traffic laws. On some roadways, why not come up with some way to provide notice to motorists?," he said.

Both cars and bike riders are expected to follow the rules of the road on streets marked with sharrows.

Sharrows will give bicyclists a guide on where to ride on the street and remind them not to ride too close to parked cars. Cyclists have a term "doored" to describe being hit by car doors opening unexpectedly.

"A sharrow does remind people to be away from car doors. It allows a car to pass and provides horizontal separation," said Hirakawa.

Miller said his company's studies are showing that bike riders are riding over the templates painted in the streets and that they are maintaining a two to six foot distance from parked cars.

Drivers should see bikes more easily on streets featuring sharrows and need to give them three feet of space when passing. Motorists are also doing a good job of giving bikes more room said Phil Miller, a designer with SvR Design.

The city has hired SvR Design to collect data on the sharrows and form preliminary plans to include in Seattle's Bicycle Master Plan. The information is being used decide what improvements the city's bicycle network requires. The plan's elements include: bike lanes; signage; policy evaluation; design guidelines; and maintenance strategies.

Miller of SvR Design says his firm is in the early stages of an implementation plan to identify streets that can accept sharrows without a major change in parking. Video cameras to record the traffic movements where sharrows are in use.

SvR Design will later be working with the University of North Carolina to study the success of the program here in Seattle. The Federal Highway Administration is monitoring the use of sharrows to see how effective they are in cities.

"San Francisco has had a good experience with them as well. They are the first to use them on a large scale," said Roger Geller, bicycle coordinator for the city of Portland, Ore.

A 2003 study by the city of San Francisco showed that sharrows moved cyclists further from parked cars. Automobiles also gave bikes more room.

As a competitive bicyclist himself who rides on city streets, Hirakawa said sharrows give him more separation from cars. "It's a smarter use of our roadway," he said.

David Hiller, the Cascade Bicycle Club's advocacy director has biked on streets with sharrows and says they don't change anything legally in regards to cars and bikes. "It reinforces where bikes and motorists are allowed to be. It is a reminder for everyone," he said.

Ballard resident and bike commuter Kevin Carrabine said it is a good idea to define routes for bikes. For people who may be afraid to ride on streets with traffic, it may encourage them to get on their bikes.

Aaron Goss, owner of Aaron Bicycle Repair in West Seattle said bicyclists already have the right of way and the city should spend money paving the roads. Goss said the surface of California Avenue, where a sharrow is planned, needs work.

They should also educate people with public service announcements. "Get drivers to stop honking at bikes and punish them for aggressive driving," Goss said.

Seattle is taking a fairly aggressive approach to sharrows because its streets have narrower right of ways than other cities with no room for additional width said Miller.

Sharrows are in use in New York City, Portland Ore., San Francisco and other cities. Los Angeles County has selected four routes it is considering for sharrows. Portland introduced them in the late 1990s and put them on streets with heavy traffic where speeds are higher.

Geller said the sharrows in Portland are only in one limited area at this time and the reaction from bicyclists has generally been positive. Portland is planning on expanding their sharrow programs to other streets.

In selecting a route, the city of Seattle developed their plan based on streets used by bicyclists that were convenient roadways for them. Engineers consider criteria such as rush hour traffic, parking restrictions, peak hours and streets often used for bike commuting.

In areas where sharrows are going in, the city places notices on people's doors alerting them to their installation and explains how drivers and cyclists are to use them.

Hirakawa said more outreach will be done at a later point to educate the general public.

The city's "Bridging the Gap" property-tax levy is providing $27 million for bike projects over a nine year period. This works out to three million annually during that time.

Bike lanes can cost $10,000 to $20,000. By comparison sharrows are inexpensive said Hirakawa, although he did not provide a financial figure.

The city is also planning to put a dedicated bike lane on 24th Avenue Northwest from Northwest Market Street to Northwest 85th Street.

Dean Wong may be reached at 783.1244 or deanw@robinsonnews.com