As cars zipped along Treat Boulevard in the pouring rain Tuesday, a steady stream of people added flowers, teddy bears and personal notes to a sidewalk memorial for Solaiman Nuri and his daughter Hadessa. Mr. Nuri and his two daughters, Hadessa, 9, and Hannah, 12, were riding their bicycles Saturday morning when a 17-year-old high school student driving a white Cadillac Escalade jumped the curb, sheared off the top of a fire hydrant and crashed into the family before hitting a building. Mr. Nuri, 41-year-old, died at the scene; Hadessa was pronounced dead at the hospital. Hannah survived with minor injuries. The driver, who witnesses said was speeding was arrested a few days later. The tragedy has shaken Concord, a city of 122,000 in suburban Contra Costa County. Like many suburbs, Concord was designed with one vehicle in mind: the car. Wide six-lane thoroughfares invite fast-moving traffic and leave little room for bicyclists. Today the city has less than three miles of painted, on-street bike lanes. Concord, with 277 bike crashes and 4 bicycle fatalities between 2005 and 2010, is not considering replacing car lanes with bike lanes using a classic non-argument: It would cause a lot of congestion. Read on in the New York Times.