March 21, 2011, 5:19 PM City Makes a Calculated Case for Bicycle Lanes By MICHAEL M. GRYNBAUM

The Bloomberg administration released an unusual two-page communiqué on Monday laying out its arguments for bicycle lanes, the subject of what one magazine has labeled the “newest urban culture war.”

The memo (pdf), written by Howard Wolfson, the city’s deputy mayor in charge of communications and government affairs, uses statistics to demonstrate improved traffic safety and cites community-based support for the lanes, which have sprouted up under the supervision of Janette Sadik-Khan, the city’s transportation commissioner.

Mr. Wolfson wrote that his memo had been prompted by a cover story in this week’s New York magazine detailing the recent civic controversy, which has now spilled into court after a group of Brooklyn residents filed a lawsuit calling on the city to remove a lane along Prospect Park West.

Some advocates have portrayed bicycle lanes as a way to nudge New Yorkers toward a more progressive, European-influenced version of city life, but Mr. Wolfson’s memo focuses more on concrete safety gains recorded by its traffic engineers.

He wrote, for instance, that injuries to drivers, pedestrians and cyclists typically drop by at least 40 percent and sometimes drop more than 50 percent along streets where physically separated bicycle lanes are installed. The memo notes that the number of bicycle crashes that lead to injuries or deaths has fallen in the last four years, even as cycling’s popularity grows.

The memo also points to a Quinnipiac University poll released last week thatfound that 54 percent of New Yorkers agreed with a statement that the lanes are a positive development “because it’s greener and healthier for people to ride their bicycles.”

Mr. Wolfson also noted that major bike lanes, like those on Columbus Avenue in Manhattan and Prospect Park West, had been approved by the local community board, and that the Transportation Department has held dozens of public meetings on the projects.

“Bike lanes are part of the city’s future,” Mr. Wolfson said in a telephone interview. “Will these save lives in the next year? You bet.”

Critics of the lanes have lodged a range of complaints, from lost parking spots to increasingly difficult driving conditions, aesthetic problems, and a risk to pedestrians from bicyclists who disobey traffic laws.

Some opponents have also faulted the Transportation Department for withholding or selectively disclosing traffic data related to bike lanes; the Brooklyn lawsuit accuses the city of deceptive practices in installing the lanes.