582: Brakes

Explain xkcd: It's 'cause you're dumb.
Revision as of 21:25, 18 April 2024 by (talk) (Explanation: They already lost a degree of control when the brakes became ineffective. (Subsequently exceeding the ability to safely/effectively steer is just icing on the cake.))
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It was the funniest 6.5 seconds of my life, although as usual like 80% of it was just Tom and Ray's gasping, hacking laughter.
Title text: It was the funniest 6.5 seconds of my life, although as usual like 80% of it was just Tom and Ray's gasping, hacking laughter.


A car's brakes fail on a winding mountain road. As a response, the driver calls a live radio phone-in show, overlooking the fact that he is in immediate danger and has no time to gather outside advice before improvising a solution. The driver fails to regain control of the car and plunges over a cliff.

If this ever happens to you,

  • Try pumping the brakes, it may rebuild enough pressure to slow you down
  • Downshift into second and then first gear, which should limit your vehicle's speed
  • Use your "emergency brake", it's not just for parking (this can damage it, but it's better than dying[citation needed])
  • Otherwise, find a safe place to coast to a stop, if possible, or else
  • Try to wreck your car in a way that won't kill you, your passengers or any other road-users/bystanders. Aim for something that will slow you down before stopping you, like a gravel turnout or a stand of bushes.


The title text refers to Tom and Ray Magliozzi who were the co-hosts of the weekly radio show Car Talk. It was a car advice/comedy radio show often aired on NPR stations. While there is some actual advice given on the radio show, it's presented as a comedy/entertainment show. Much of the show did involve the hosts "gasping and hacking" as they ask non-relevant questions of the callers and add their own commentary or relate other personal asides and stories.

Since he claims that he has 6.5 funny seconds, he must have connected with them way before going over the cliff. Because in 6.5 seconds a car would fall approximately 200 m (½*g*t^2, with g = 9.81 m/s^2, and t the time in seconds. This will give 207 m, but there will be a lot of air resistance). It is clear from the drawing that the car is still going almost straight out into the air, so it is still almost at the height where it left the road at quite a high speed (to get this far away without turning the engine down towards earth yet.) And the front of the car is just about 5 car lengths to the ground, which would make this a 10-15 m drop only (which would take less than 2 seconds to fall). But according to the comic it seems like he first connected with the show, just when the car has left the road...


Of the potential responses to my brakes' failure, I did not choose the best.
[A cliff is visible, with a car flying off it, and trees below.]
Voice from car: Hello, you're on Car Talk.


  • NPR made a shirt out of this comic; it can be seen at shop.npr.org.

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The shirt would have been even better if they would have put the alt-text underneath! -- mwburden 20:53, 12 December 2012 (UTC)

Car Talk wasn't a live call-in show! You call them, and they call you back, and it's edited into a show structure! 00:48, 23 January 2014 (UTC) True... but the version in the comic has to be a live show for the joke to work, and most listeners, unless they called in, probably didn't realize it wasn't live somewhere. 03:45, 29 August 2015 (UTC)

The t-shirt link leads to a 404 from NPR's wobsite. -- T 22:07, 6 December 2016 (UTC)

The 6.5 seconds could refer to a non-immediate death on impact, solving the conundrum posed by timing of physics and communication in the explanation. -Arkady Darrel 03:46, 22 February 2017 (UTC)