Cambridge Civic Journal Forum

I am expanding here on comments which I made on a post in the Cambridge Bikes Facebook group.

The overhead view from the post shows a stretch of Huron Avenue near Sparks Street.

Huron Avenue and Sparks Street

I see here a retrofit to a car-centric street design in an attempt to accommodate bicyclists of all ages and abilities, a popular goal of bicycling advocacy.

This stretch is downhill right to left in the overhead view. A common explanation for the buffer (diagonally-striped area) to the left of the bike lane is that it is to protect cyclists from overtaking motorists — but it places the bike lane in the door zone. A bike lane in the door zone is unsafe for any bicyclists, but it is worse here. Motorists don’t have x-ray vision. A look in the driver’s side mirror won’t show a bicyclist until rather late on a right-hand curve: bicyclists are hidden by the parked cars behind. Bicyclists can travel as fast or nearly as fast as cars here, also worsening the dooring hazard. and do best to merge out and ride in the stream of motor traffic. This also improves sight distance for motorists who might (horrors!) have to slow a little to follow a bicyclist.

On the other side of the street, the bike lane leads bicyclists into the right-hook zone at Sparks Street in the expectation that all right-turning motorists will yield. The green-painted crossing is an attempt to accommodate bicyclists who do not check for traffic behind them, whether due to lack of skill, a stiff neck, inattention or misplaced trust. But, not all motorists yield. A bicyclist needs to be extra careful here, casting a look over the shoulder, and preferably merging left to block a right-turning motorist or let that motorist pass on the right.

Is it actually possible to design safely for all ages and abilities here? A speed hump could help by slowing motor traffic. Removing parking spaces would make a big improvement, but parking spaces are sacred to residents and business owners, and illegal parking (as in the bike lane on the south side) is tolerated as a minor sin. Moving the legal parking to the uphill, soutth side, would reduce the dooring risk. On the south side, bicyclist are traveling more slowly and sight lines are better.

But above all, a major change in motorists’ behavior is needed — a cultural change: reduction in speed, and respect for bicyclists who safely far enough from the parked vehicles to avoid dooring. Attempting to bring about bicycling accessible to people of all ages and abilities using paint first, without the public will to step up enforcement, gets things backwards. In the mean time, children might ride slowly on the sidewalk, but grownups do best to use defensive driving techniques, as I have described.  The major motorist behavior change can be expected (with autonomous vehicles) — in a decade or three.  If  shared use becomes dominant with motor vehicles, there also will be less need for parking spaces and that would be good too.