New York City is in the midst of a cycling boom. New Yorkers are riding bikes more than ever, both as a commuting option and a recreational activity. But with that growth has come a steady increase in the number of riders who flout traffic laws, ignoring the fact that their actions can have tragic consequences.

I know this firsthand. On March 9 at about 6:30 p.m. in Washington, my mother, Jane Bennett Clark, stepped onto the street on her way to the subway after work. It was an unseasonably warm and beautiful day, and I like to think that as she stepped off the curb she was in a cheerful mood, thinking about the weekend ahead.

Those were among her final conscious moments.

Seconds after she set foot in the crosswalk, a cyclist plowed into my mother with such speed that he broke her collarbone and multiple ribs. (My mom, who followed pedestrian laws with a near-religious fervor, had a green light.) She fell back on her head, fractured her skull and lost consciousness soon after. The cyclist was cited for disobeying a traffic device. The next day, my mother was declared dead at the hospital.

She was 65, a journalist, a mother of three, a partner, a daughter and a new grandmother.

My mom was struck in Washington, but it could have happened in New York. Both are among the most bike-friendly cities in the country. As The Times reported last month, there are more than 450,000 daily bike trips in the city. With 10,000 Citi Bikes and ubiquitous bike lanes, the streets are more hospitable than ever to bicycle commuters. And those increases aren’t unique to New York. Between 2000 and 2013, bike-commuting rates increased 62 percent on a national average, according to the League of American Bicyclists.