One source of contention -- and site of crashes -- between bicyclists and drivers is Capitol Hill's bike lanes on Pennsylvania Avenue Northwest, which run down the center of the road.

Bicyclists say drivers are making illegal U-turns in front of the bike lanes, leaving fast-moving bikes no option but to try to screech to a halt or ram into the cars.

"We know the U-turns are leading to crashes there and near-misses on a daily basis," said Shane Farthing, executive director of the Washington Area Bicyclist Association.

Cyclist Dave Salovesh uses the lanes to bike to work in Penn Quarter and take his 9-year-old daughter to school.

"I've taken four trips with her so far, and on two of those trips we've had somebody made a U-turn on the same block with us," he said.

Salovesh was hit last fall when a driver made a U-turn in front of him in the bike lanes. Salovesh was able to slow down in time to avoid being injured, but he was still upset, he said.

"He didn't act like it was his fault. ... You've got to be pretty careless to think that those 'no U-turn' signs only apply right when you're next to them," he said.

Salovesh said he's had conversations with cab drivers who make the U-turns frequently.

"They understand it's wrong, and that's why they stop to look so carefully. Or [they say] that everybody does it, and nobody would really expect them to drive all the way around the block," he said.

A D.C. police commander for the 1st District recently promised residents that police would step up "no U-turn" enforcement along the avenue.

But Capitol Hill resident Jennifer Rosen says it's not just cars causing the danger on the road.

"Cyclists are constantly veering in and out of those lanes whenever they want to. They're not respectful of the path itself," she said.