Mayor Newsom's enthusiasm for innovative best practices from around the world is well known; trips to Davos and Chicago open the Mayor's eyes and stretch his imagination, from free WiFi to free Muni to green streets. The Mayor was quite entranced by the bike-sharing system used in Lyon, France — with built-in circuitry to work the sharing part and rugged design to withstand being left out in Lyonnaise weather and street life. The Lyon bike-sharing system has been a smash, with tens of thousand of people using them each day. Alas, if only our Mayor were as enthusiastic about other, simpler, greener French urban design.

The Paris Plage, a temporary beach made in the middle of the city every summer on a few miles of riverside expressway, plops much-appreciated recreational space and promenading lanes into a densely-populated metropolitan area. Paris Mayor Betrand Delanoe appreciates the benefits of reclaimed streets; another of his programs designated several "Paris Respire" (Paris Breathes) zones, where driving is not allowed on Sundays or holidays.

Here in eco-progressive San Francisco, where we wait forever for even a 6-month trial of car-free roadway in Golden Gate Park, we yearn for some international best practices for our public realm, something green and smart. Paris and Berlin and Bogotå and Chicago and New York get greener, but we wait.

There's one venerable roadway innovation that we've been waiting for years to try here in San Francisco: bike lanes paved in a distinct color. The Dutch and Germans do dark red bike lanes, the Danes and Brooklyners do blue, the Irish have green. It's really more of a convention than an innovation – folks in Europe have been riding their bikes on colored lanes for decades.

If you've ever been so fortunate as to ride a bicycle in the Netherlands or Denmark you know what a difference it can make to have the "bike space" in the roadway called out directly by a different colored pavement. Declaring bicyclists' right of way in such a readily visible manner grants the bicycle a higher legitimacy in an urban streetscape, and is part of the Dutch and Danish formula for successful mode shares for cycling (39% of trips take place by bike in Amsterdam, 36% in Copenhagen; San Francisco sees probably 5% of trips by bike and aspires to 10% by 2010, per our official Bicycle Plan).

Of course, you don't need to travel to Europe to ride your bike on colored lanes. Brooklyn's got some blue bike lanes, as does Portland, Oregon. We hear that even Sunnyvale has some blue bike pavement now, and Petaluma put down some red bike pavement a while ago.

Colored pavement technology is actually pretty pedestrian these days. Generally the pavement coloring is achieved not by plain paint, which tends to be slippery when wet and not too durable, but rather by coloring the paving medium itself, asphalt or composite material. For retro-fitting existing streets, a simple paving slurry, dyed to the appropriate color, is spread out like peanut butter over the roadway, then ground smooth, leaving a thin layer of colored bike lane. As the pavement wears, the color keeps up (bike traffic wears down roadway much more slowly than cars and buses do). Long strips of colored bike lane can be implemented quickly in this way.

In August 2004, the Board of Supervisors passed legislation to forbid the eastbound right turn off of Market Street onto the Central Freeway at Octavia Boulevard (more than a year before the rebuilt and reconfigured freeway ramp opened to traffic). As part of the prohibition on the right turn, the Board asked DPT (now MTA) to implement a number of safety measures at the intersection, including colored-pavement bike lanes. Almost as soon as the Boulevard opened, cyclists and pedestrians found themselves imperiled by motor traffic making heedless turns onto the Freeway, and bicycle knockdowns and collisions began to occur more and more often. The MTA sluggishly worked at installing simple conventional signage at the intersection, the bare minimum (perhaps not even that much), and no colored bike lanes.

A year ago Mayor Newsom instructed the MTA to go ahead with an initial implementation of green bike lanes at the Market / Octavia / Central Freeway intersection, requesting that it be complete in time for Bike to Work Day 2006 (May 17). But May came and went and still no colored bike lanes.

This past January saw the terrible run-down of Margaret Timbrell, a cyclist pedaling to work down Market Street who was crushed by a tradesman's truck making the illegal turn at high speed onto the Freeway. Public outrage boiled over, Supervisors paid attention, and the MTA came out with a few more fixes ("safe hit" posts, a string of plastic sticks hot-glued to the roadway, forming a simple fence to discourage motorists from making the illegal right turn), and promised a little traffic island. But still no colored bike lanes.

So why hasn't the MTA moved forward with bikeway color treatment, at the Market/Octavia intersection or anywhere in the city? How could the MTA just say no to Mayor Newsom's order to go forward with colored lanes on Market Street?

Design immunity vs. liability, that's why. Although colored bike pavement is described as a design tool in the official Bicycle Plan adopted by the Board of Supes in June 2005, the MTA says that colored bikeway pavement isn't ready for San Francisco, because it's not an accepted "traffic control device" recognized by Caltrans or the Federal Highway Administration. There's no official standard in the design manuals maintained by the official highway agencies, as there is for STOP signs and double yellow lines, and MTA's engineers don't stray from the box defined by the highway design manuals.

So far nobody in California or Washington DC has written up specs on colored pavement for bike lanes, so SF's traffic engineers are unwilling to use the "device" for fear of legal liability: someone could use the nonstandard bike lanes against the city in a lawsuit. That's right, someone might claim that they didn't know what they were doing when they ran the red light because they were confused by the green bike lane.

The MTA may be killing us with caution; liability exposure for poor roadway maintenance is much greater than anything that might come from colored pavement. It's time for anxiety about a decades-old roadway marking convention to yield to reason, and the impulse for best practices followed. Courage, Mr. Mayor, we're San Francisco, the city that knows how, we can lead as well as follow. We're ready for True Green Streets to bloom in San Francisco, on Market, in Golden Gate Park, all over the city. No more waiting.