Chart of the Day: Kinetic Energy of Bicycles versus Cars

Via the Twitter feed of Juan Melli, a resident of New Jersey, here is a chart showing the kinetic energy (i.e. energy generated because of motion) of a bicycle going 20 miles per hour versus a car going 30 miles per hour.

It’s a pretty one-sided chart:

Melli writes that:

Kinetic energy that would hit a person by a 20 mph bike (🤕) vs 30 mph car (☠️) and why ‘equal’ enforcement of cars, bikes, and peds is an allocation of resources that ignores the risk profile & doesn’t maximize safety/minimize the death rate (Chart credit: )

Of course, most cars are not traveling at 30 miles per hour much of the time, and people riding bicycles travel slower than 20 most of the time, so this chart is most often even more imbalanced.

The point, for me, is that narrative “equivalence” of bicycles and automobiles as dangers, threats, or causes of safety problems in our cities is not an accurate picture of the physical reality of the vast majority of situations. is a non-profit and is volunteer run. We rely on your support to keep the servers running. If you value what you read, please consider becoming a member.


3 Responses to Chart of the Day: Kinetic Energy of Bicycles versus Cars

  1. Walker Angell
    Walker Angell May 11, 2018 at 12:38 pm #

    Why then do people in NYC fairly consistently say that they are more fearful of bicycle riders than car drivers?

    • Chris Moseng May 11, 2018 at 12:56 pm #

      If you’re driving a car in NYC you’re lucky to get up over 10 mph. Gridlock and other obstacles (a critical mass of pedestrians crossing at a light, for example) compel them to travel at “safer” speeds. I don’t think that’s really an optimal solution or attainable goal outside of NYC, though.

  2. Chris Moseng May 11, 2018 at 12:59 pm #

    The constant need to educate people about the massive (pun intended) physics differences between operating a motor vehicle and riding a bike is frustrating. Responding to a bus fatally striking a bike by blaming the biker for “obviously” “going too fast” requires some mind boggling ignorance, but you have to be nice when you say so.

Note on Comments welcomes opinions from many perspectives. Please refrain from attacking or disparaging others in your comments. sees debate as a learning opportunity. Please share your perspective in a respectful manner. View our full comment policy to learn more.

Thanks for commenting on!