I witnessed a bike-on-bike crash today. Luckily, everybody was OK, but the crash illustrates an important problem with our infrastructure.
I was heading South toward Main St on the new two-way bike lane on Ames St, riding behind one other person. Right after we passed Cava, at the driveway leading toward Google / Kendall Center, another person on a bike swooped across the bike lane, apparently taking a left from the southbound travel lane on Ames, and crashed into the person in front of me. Thankfully, they both got up, inspected themselves, and appeared to be OK.
Now, you might think, 'huh, sounds pretty reckless on the left-turner's part', and you wouldn't be wrong. However, there was another contributing factor worth considering: a catering van was illegally parked exactly in the daylighting spot intended to prevent such incidents. See my photo of the scene below. While it's true that the left-turner should have noted the limited visibility and the obvious bike lane, and proceeded cautiously, but I think that gives an unfair pass to the delivery driver who created an unnecessarily dangerous situation in the first place.
If you look at the picture, the problem might become more clear: there's nothing physically preventing the driver from parking in the daylighting spot. This is true in a concerning number of our protected bike lanes (see also the South Mass Ave lanes). I understand the pressure to conserve flex posts (which are hideously expensive), but we really need to account for the fact that people will park anywhere they aren't physically blocked from accessing (i.e. paint is not protection). It's possible that a single additional flex post might have made this incident much less likely.