Because of this accumulation of dangers, any major upgrade of Comm. Ave. should incorporate protective bicycle infrastructure, such as the segregated lanes known as cycle tracks. But after four years of planning for a $16 million overhaul of the three-quarter-mile section between the BU Bridge and Packard’s Corner, the city’s current design pays too little heed to cyclists. The redesign includes a federally required widening of the avenue’s median to provide more passenger and maintenance access to the Green Line T. The plan also calls for more left-turn lanes for cars. But the avenue’s 5-foot-wide bike lane, too narrow to protect cyclists from carelessly opened car doors, remains.

From 2010 to 2012, there were 70 bicycle accidents reported on the stretch of Commonwealth leading from the BU Bridge to Packard’s Corner in Brighton. Seventeen of them involved car occupants opening doors into the path of cyclists. The crash that killed Christopher Weigl, the BU photojournalism graduate student who was struck by a turning tractor-trailer, occurred on that stretch, too.

Few Boston roadways scream out for redesign more than Commonwealth Avenue does. The spine of Boston University and a connector of commerce from Kenmore Square through Allston and out to Boston College, the avenue abounds with speeding traffic, fearless pedestrians, weaving buses, and double-parked vehicles. But it also accommodates a growing number of bicyclists — 5,000 a day — whose safety must figure into a pending reconstruction of the roadway.

James Gillooly, the city’s interim transportation commissioner, said most of the changes were consistent with federal guidelines, and that a wider bike lane would have meant less space for car lanes or sidewalks. But failing to accommodate cyclists carries its own cost to the city’s transportation objectives. Boston has set a target of increasing its percentage of bike commuters from the current 2 percent to 10 percent by 2020. But no city, not even bike-friendly Amsterdam or Copenhagen, has achieved such high levels of cycling without protected bike lanes. Motorists benefit from forward-looking planning, too. Cities well designed for bicycles, walking, and public transportation almost always reduce car traffic on crowded thoroughfares like Commonwealth Avenue, with its 31,000 to 36,000 automobiles a day.


Facing a petition drive and last-minute pleas by activists, Gillooly promised to look into creating an additional 3-foot buffer for the existing bike lane by slightly narrowing the car lanes and the T median. But the conflicts with cars will remain.


Meanwhile, it’s disappointing that the Comm. Ave. plan got this far without a better provision for cyclists. Many cities in Europe, with streets and sidewalks much older and narrower than Commonwealth Avenue, have figured out how to incorporate safe biking infrastructure. If a safe cycle track cannot be installed on one of Boston’s widest and straightest thoroughfares, it bodes ill for the city’s broader plan for cycling and its dreams of curtailing congestion.