Mexico City - On November 17, a 21-year-old woman who was using one of the city's bike-share cycles was mowed down by a bus. She was riding in a lane that gives bikers priority. Two days later, another cyclist was killed by a semi-trailer truck. Both accidents have sparked outrage about officials' inability to ensure cyclist safety even as they encourage more people to ride.

"We can't tolerate speeches and programs without funds because without money, good intentions won't lead to any results," biker-rights groups said in a letter to the authorities in which they requested a commitment of 200 million pesos (about $12 million) to improve biking infrastructure. The biking advocates say they've recorded 22 cyclist deaths in Mexico City so far this year. The official count, meanwhile, is nine.

Mexico City has been pushing a series of bike-friendly policies as it tries to curb traffic and pollution. In 2007, it started clearing one of the city's main thoroughfares from car traffic on Sundays, so bikers, skaters, and pedestrians could take over. In 2010, it started a bike-share program, which has since offered nearly 29 million rides (link in Spanish). The program, called Ecobici, is used by 100,000 people every week, officials say.

But the city's traffic, considered among the world's worst, is still wild and unwieldy, even to locals. Nearly three people are killed daily in traffic accidents in Mexico's Distrito Federal, which encompasses a large swath of Mexico City, and another 20 are injured, according to government statistics from 2011 (p. 66), the latest figures available. The data doesn't break out the number of dead or injured cyclists, but bike accidents in general are on the rise.

On November 22, dozens of riders, along with relatives of the biker killed on Nov. 17, gathered to paint a butterfly-winged cyclist at the accident site, as a memorial. Since both of the fatal accidents last week, the city's government has launched an ad campaign to educate drivers to watch for cyclists, and has said it will hand out up to 40,000 reflective pink vests. The city also plans to launch new set of traffic rules next month that give pedestrians and cyclists priority.