…how do you know that? I thought roads, in north America at least, were set on the 85 percentile rule. Measure how fast people are going on a street and set the speed limit to the car at the 85 percentile, rounded.
This sounds like “common wisdom” to justify speeding. And even then, you would never know when the road you are on actually has a correct speed limit and you’re endangering everyone. A 5 - 10 mph increase is a lot more dangerous than one may think, because the energy in the system increases quadratic and the reaction time remains constant, it’s even dangerous at 5-10 kmh.
Speed limits are set by civil engineers using a whole host of scientific data, local ordinances, state laws, and FHA rules.
You’re vastly overestimating the sophistication involved in speed limit setting. Look up the concept of 85th percentile speed for more information.
As a caveat, this doesn’t apply to every country, but it certainly appears to for the U.S, given that multiple DOTs list it as the “common method for setting speed limits”.
Well I wouldn’t know, but I saw this video, which says this is how it is described in “Confessions of a recovering engineer” by Charles Marohn, former professional engineer. If you or your ex find any fault with what Charles wrote or what NJB got wrong in adapting part of the book into his video, let me know.
…how do you know that? I thought roads, in north America at least, were set on the 85 percentile rule. Measure how fast people are going on a street and set the speed limit to the car at the 85 percentile, rounded.
This sounds like “common wisdom” to justify speeding. And even then, you would never know when the road you are on actually has a correct speed limit and you’re endangering everyone. A 5 - 10 mph increase is a lot more dangerous than one may think, because the energy in the system increases quadratic and the reaction time remains constant, it’s even dangerous at 5-10 kmh.
NOT SINGLE ROAD in this country is set by “how fast people drive” that is without a doubt the stupidest thing heard in a long time.
Speed limits are set by civil engineers using a whole host of scientific data, local ordinances, state laws, and FHA rules.
I wish I could send this to my ex (a certified civil engineer) she’d die laughing.
You’re vastly overestimating the sophistication involved in speed limit setting. Look up the concept of 85th percentile speed for more information.
As a caveat, this doesn’t apply to every country, but it certainly appears to for the U.S, given that multiple DOTs list it as the “common method for setting speed limits”.
Well I wouldn’t know, but I saw this video, which says this is how it is described in “Confessions of a recovering engineer” by Charles Marohn, former professional engineer. If you or your ex find any fault with what Charles wrote or what NJB got wrong in adapting part of the book into his video, let me know.