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> To be fair, this behaviour isn't one-sided. Often bicycles, e-bikes and motorcycles squeeze through small gaps between cars moving slow'ish in packed traffic.

> To be fair, this behaviour isn't one-sided. Often bicycles, e-bikes and motorcycles squeeze through small gaps between cars moving slow'ish in packed traffic. The speed is the issue. A collision at low speeds is much less likely to be fatal [0]. Being closely overtaken by a car when you're going at 20-25mph on a bicycle is 1) a scary experience and 2) unnecessarily dangerous for the cyclist (and not at all for the driver). [0] https://nacto.org/docs/usdg/relationship_between_speed_risk_fatal_injury_pedestrians_and_car_occupants_richards.pdf https://nacto.org/docs/usdg/relationship_between_speed_risk_...

throw0101a 5y ago
Instead of digging through that PDF, the charts on this post show how a higher speed can drastically increase the odds of fatalities: * https://usa.streetsblog.org/2016/05/31/3-graphs-that-explain-why-20-mph-should-be-the-limit-on-city-streets/ https://usa.streetsblog.org/2016/05/31/3-graphs-that-explain... Remember from physics class that kinetic energy is generated proportional to the square of velocity. Doubling speed quadruples energy.
- HPsquared 5y ago
  Not only does speed increase the damage inflicted by a given collision, it also makes them more likely: there is less time available to see and respond to hazards, and the space required to stop also is proportional to (speed^2). So for a given road, the risk level (frequency * consequences) is probably even steeper than squared: perhaps more like (speed^3).
  - clairity 5y ago
    no, this is an all-too-common misconception, because you’re missing the other half of the distribution where accidents were avoided because the car speeded past an accident that would have happened at a lower speed. speed increases the severity of an accident (e.g., more fatalities vs. injuries), but doesn’t generally cause the accident. distractedness and impairment are overwhelmingly the primary causes of auto accidents. it’s important for policy decisions that we keep this very clear, and why we have ineffective, revenue-oriented programs like speed enforcement rather than attention-oriented policies.

throw0101a 5y ago

Instead of digging through that PDF, the charts on this post show how a higher speed can drastically increase the odds of fatalities: * https://usa.streetsblog.org/2016/05/31/3-graphs-that-explain-why-20-mph-should-be-the-limit-on-city-streets/ https://usa.streetsblog.org/2016/05/31/3-graphs-that-explain... Remember from physics class that kinetic energy is generated proportional to the square of velocity. Doubling speed quadruples energy.

HPsquared 5y ago
Not only does speed increase the damage inflicted by a given collision, it also makes them more likely: there is less time available to see and respond to hazards, and the space required to stop also is proportional to (speed^2). So for a given road, the risk level (frequency * consequences) is probably even steeper than squared: perhaps more like (speed^3).
- clairity 5y ago
  no, this is an all-too-common misconception, because you’re missing the other half of the distribution where accidents were avoided because the car speeded past an accident that would have happened at a lower speed. speed increases the severity of an accident (e.g., more fatalities vs. injuries), but doesn’t generally cause the accident. distractedness and impairment are overwhelmingly the primary causes of auto accidents. it’s important for policy decisions that we keep this very clear, and why we have ineffective, revenue-oriented programs like speed enforcement rather than attention-oriented policies.