dr2blog

(to 311@cambridgema.gov)

Possible change to light timing at Garden, Huron, and Sherman.

I bike on Garden to and from work every day, I get plenty of chances to study this light’s behavior. Right now it has a sensor trigger for Garden traffic, and a button-requested all-ways pedestrian signal. The default timing when traffic is present is pedestrian traffic, Garden, Sherman, Huron from the south, and then Huron both directions. It’s relatively common for people bicycling (usually on Garden) to proceed during the pedestrian signal, usually slowly and avoiding pedestrians, but apparently not always; I’ve read some complaints on social media from people who live near there of bikes not yielding to them in the crosswalk. It is, on the other hand, slightly safer for bicycles to cross the intersection when no cars are in motion, so there’s a bit of a tradeoff there, even though the safer bicycle behavior is technically illegal.

I don’t know all the constraints on the light timing so the following suggestions might not actually be useful, but if possible, these might help with the bicycle-pedestrian conflicts.

Possible change #1: rearrange the light timing so that the light for Garden goes green before the pedestrian signal, not after.  That is, pedestrian, Sherman, Huron-from-the-south, Huron, Garden.

With the current timing bikes accumulate during the Sherman and Huron phases, so if there are bikes, there will usually be some waiting when the pedestrian phase begins, and some of those will run it, and some of the runners will not yield to pedestrians. With the rearranged timing, those bikes will go during the Garden phase and clear the intersection before the pedestrian signal. Some who arrive during the pedestrian cycle may still run their red, but there will be many fewer, and also arriving later in the phase after pedestrians were already in the crosswalks.

Possible change #2: legitimize the running, but try to control it. Five seconds after the pedestrian cycle begins, change the red bicycle signal to flashing red, for stop-then-go. Possibly also include a “yield to pedestrians” sign, possibly include a red yield triangle in the bike lane.

The hope here is that daily cyclists would learn they could cross legally after a short delay, and start to wait for the delay. This is somewhat speculative since, at least from what I see, most cyclists running the light are already doing it carefully and the ones who are not and create conflicts with pedestrians either don’t care or are clueless, and might not respond to this nudge. On the other hand, this will not make things worse, and will provide a small time and safety savings to careful cyclists, and legitimize careful cycling.

These two changes could be combined, though from a “does this work?” point of view that would muddy the waters if this was regarded as an experiment. I think the first choice would work better and cost less to implement.

In words, there is a parking-proteected bike lane on the north side of the street at 1575 Cambridge (and Dana), and it approaches a crosswalk. When the lane was installed (there’s a picture in Google Maps, I attached it) there was a small utility box just before (east of) the crosswalk, shorter than a person (though not shorter than a child).

Since then the utility box has been replaced, and the new one is larger, and it is about as tall as a person. It is now more than adequate to hide a pedestrian who wants to cross, and someone in the bike lane would not see them until perhaps 1.4 seconds before reaching the crosswalk. The attached pictures showing proposed changes were taken 1.4 seconds before reaching the crosswalk at 14mph, I have GPS-annotated video. Some people travel faster than 14mph.

I think this is a hazard waiting for just the wrong timing to result in a crash, and of course, everyone will blame the “irresponsible bicyclist”, instead of whoever designed this blind intersection. If nothing else, this email will put something in the records for later discovery.

This is the second time I’ve been caught like this, I have tried to train myself to swerve away from what I cannot see but humans make mistakes. This intersection should be fixed.

Proposed fix #1 is to move the crosswalk so that it starts before the box and is slightly diagonal to the corner. I think this would require moving a car parking space one slot down the road.

Proposed, lesser-but-easier, fix #2 is to shift the bike lane away from the curb, at minimum with paint, to give a clue that it would be a good idea to leave some room. This will work less well because not everyone will follow the shift and it’s not that much extra room.

I am not sure warning signage would be a net help; there’s already trees and signs and those boxes and the parked cars give poor visibility of people crossing from the Dana side.

I think it would also be helpful to review whatever processes allowed this hazard to be created.