Confusing intersection: video and quiz

One afternoon in October 2024, I rode my bicycle on Mount Auburn Street in Cambridge, Massachusetts, shooting video with front and rear cameras. I rode through the confusing intersection with Putnam Avenue. This post includes a video clip of my ride through that intersection.

For your information also, here is a link to the intersection in Google Maps. I was coming in from the west on Mt. Auburn Street, next to the longest side of the building with the odd notched facade.

I rode through this intersection hundreds of times when I lived in Cambridge, but I hadn’t yet ridden through it with its new lane configuration and traffic signals.

Your mission, should you care to accept it

Several people figure in the video:

• A motorist;
• Three cyclists, of whom I am one;
• A pedestrian.

Please view the video and think about their actions, from the points of view of

• Safety;
• Courtesy;
• Legality;
• Unexpected and unintended consequences.

Let’s roll the video

Traffic signals and signs are important too. Let’s roll the video and see how it plays out.

My evaluation

OK, here is my own own evaluation. Quick summary:

• The motorist was operating legally and cautiously, turning from the designated turn lane and using turn blinkers. But the motorist had to figure out what to do at this unusual and confusing intersection where the right-turn lane is the middle lane, with a through lane for buses and bicycles to its right.
• The first cyclist who passed me (on the e-bike) was discourteous and reckless in passing me closely. That cyclist also was reckless in passing on the right of a car with a right turn blinker flashing. There was no way to know when the right-turn arrow would come on. The cyclist did stop and yield to traffic in the intersection before crossing it.
• The cyclist who passed me on the right and sped out into the intersection could very well have ended up on the hood of the car if it turned right on the new green.
• But — my inviting the driver to proceed could have caused a crash if the cyclist had arrived a few seconds later. I never noticed the cyclist till he passed me. I need to look all around before giving such an invitation again.
• The City of Cambridge has no signal which applies to cyclists who are expected to pass on the right in the bus-bike lane. The horizontal white bar bus signal (equivalent to a red light for buses) indicated that buses in the right-hand lane should wait. It may change only when a bus arrives.

This could have turned out worse!

Comparison with another confusing intersection

Also see the follow-up article looking at this intersection from a motorist’s point of view. Another recent article shows how a confusing intersection can be tamed by following the rules for drivers of vehicles. How would that strategy work here?

Your turn! I’ll be reading your comments and following up on them.