Where would a small number of curb changes make the biggest difference for people biking in Cambridge? We used recent Bike Bureau reports to find out.
Between July 4 and August 18, 2026, riders submitted 355 public reports of vehicles blocking Cambridge bike lanes. Each report is a documented obstruction at a specific place and time. Taken together, they show that the problem is citywide—but not evenly distributed.
A cyber truck cyberparked in a mass ave bike lane [bb/report/1il]
What the map shows
We asked a concrete question: what is the smallest number of 200-meter-diameter areas needed to contain at least half of these recent reports?
The answer is 12 areas. Together, the 12 circles on the map contain 181 of the 355 reports, or 51%. Eleven circles can contain at most 174 reports, so 12 is the proven minimum needed to reach half. The n inside each circle is the number of reports in that area.
The busiest area contains 38 reports. The next contains 23, followed by 18 and 17. That concentration gives Cambridge a practical starting point: instead of treating every blocked bike lane as an isolated incident, the city can investigate the places where obstructions keep recurring.
This was optimized, not eyeballed
We analyzed every public Cambridge Bike Bureau report in the 45-day window. Coordinates were projected into a local metric map, and the analysis enumerated every geometrically relevant 100-meter-radius circle. Because we wanted to be fancy, we applied a binary optimization model to find the fewest circles needed to cover at least half of the reports. After proving that minimum, it selected the placement of those circles that covered the most reports.
The solver returned a zero optimality gap. In plain English: 12 is not a visual guess or the output of a generic map-clustering effect. Given the reports, the 200-meter diameter, and the 50% target, 12 is the mathematical minimum.
What should Cambridge do?
Bike Bureau reports measure observed bike-lane obstructions, not every obstruction that occurred. Places with more riders or more active reporters can be represented more heavily. But even if we can't prove that fixing these areas will have the most impact theoretically possible - we can say for sure that they are serious problems and fixing them could only require a few well-placed loading zones and protected curb treatments prevent recurring obstructions.
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