LOS ANGELES — Mayor Antonio Villaraigosa is the new champion of cyclists' rights in the nation's second-largest city, a conversion that came after a bone-breaking fall from his own bicycle.

The mayor, who said little on the topic during five years in office, is campaigning to make streets safer for cyclists after a parked cab abruptly pulled out across a bike lane, causing him to shatter an elbow. The ill-fated ride was his first on city streets since taking office.

Since the July 17 accident, Villaraigosa has utilized the Huffington Post and YouTube to say that it's time to recognize that bicycles also belong on LA's streets, which were largely designed for autos. In the YouTube video, he announced plans to convene a bicycle safety summit.

Cyclists who have tilted at LA's car-crazy culture for years were shocked that the mayor was even on a bike.

"You could have knocked over any cyclist with a feather when we heard that," joked Ted Rogers, author of the blog BikingInLA.

Others in the activist bicycle camp remained beyond skepticism, dismissing the summit Monday in advance as a failure because it's scheduled downtown during weekday work hours when they can't attend.

Compared to cities such as New York, San Francisco and Washington, D.C., that have added miles of bike lanes among other measures to promote bicycle commuting, Los Angeles has been stuck in the slow lane.

Good weather and a significant amount of flat terrain would seemingly make the city ideal for commuter and recreational bicycling. Its hilly areas are prized by competitive cyclists for challenging rides on canyon roads.

There is also a legacy dating back more than 100 years, when a wooden bikeway was built for commuting between Los Angeles and suburban Pasadena. The bikeway fell victim to the automobile and the route eventually became a freeway, but LA and its neighbors never fully gave up on cycling.

In recent decades a bike path along Santa Monica Bay beaches has grown to 22 miles and one of Villaraigosa's predecessors, Richard Riordan, spent two terms leading huge community bike rides.

Yet cyclists say riding in Los Angeles can be terrifying, as they jostle with cars and buses on tightly-packed roads.

"I've been spat at, cussed at, and knocked down in a road rage incident," said William Cruz, 21, who commutes by bike about 20 miles a day. "It makes you paranoid at times."

Cycling advocates believe more people would turn to pedal power if roads were safer. Frustrated by lack of progress, some have taken up guerrilla tactics by painting bike lanes and other cycling symbols on roads and street corners.

A group of cyclists once rode onto a major freeway interchange to zip through jammed traffic, and mass rides to demonstrate cyclists' rights have frustrated motorists.

Others came up with a "Backbone Bikeway Network" — their own version of a citywide bike map designed to get around town faster on major corridors.

As neighboring cities such as Santa Monica and Long Beach provide bike valets, bike lanes and other improvements to encourage cycling, Los Angeles is starting to do the same.

This summer, the transportation department began painting "sharrow" markings on several streets after two years of study and delays. The markings are used to remind motorists to share the road where there is not enough room for a separate bike lane.

The city is also updating its bicycle plan, which envisions 1,633 miles of bike lanes, paths and routes. Cyclists, however, remain dubious. The last plan called for 526 miles of bikeways, but so far only 354 miles exist — a fraction compared to the city's 7,200 miles of roads.

Villaraigosa says the city needs to invest in bicycling infrastructure and focus on traffic safety enforcement to make streets safer for cyclists.

"We also have to have a cultural paradigm shift," Villaraigosa said in an interview with The Associated Press. "We have to recognize that even in the car capital of America, drivers have to share the road."

He plans public service announcements and will ask broadcasters to run bike safety messages.

About $3.2 million will be set aside for bicycle and pedestrian improvements in the 2011 fiscal year, he said.

The Los Angeles Police Department has already begun cracking down on motorists who don't respect cyclists' rights.

Recently, the department changed policy by assigning traffic officers instead of beat officers to investigate clashes between bikes and cars. Cyclists had complained that police refused to take reports if no collisions occurred, even when a motorist made a careless maneuver that caused a cyclist to fall.

The relationship between police and some cyclists remains far from cozy. In May, a mass ride in protest of BP's Gulf of Mexico oil leak led to a confrontation with officers and a YouTube video appeared to show an officer kick at a passing cyclist. An internal investigation is under way.

Bicycling proponents are also upset that Villaraigosa did not press charges against the cab driver after his fall.

"He needs to be clear on who pays for that," said activist Stephen Box.

Villaraigosa said he was not in a position to decide whether the cabbie committed a violation.

"It was an accident. The Police Department may end up citing him, it's not something I'm involved in," he said.

Villaraigosa said he rode in his 20s and has occasionally biked by the beach.

"I knew the hazards that come with cycling in LA but I hadn't been on the streets in a while," he said.

The injury — and the eight new screws in his right elbow — are likely to be permanent. The mayor said he does not expect to regain full extension of his arm, but he expects to eventually get back on a bicycle.