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32000 bikes on Berlins Autobahn
(i.imgur.com)
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this post was submitted on 03 Jun 2024
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Looks to be an average of 2 ppl per lane with 3m ahead & behind. An average biking speed for commuters is 18-29kph, so let's do the calculus for 20, 25, & 30. This gives a throughput of 2x3x(20 or 25 or 30)/(3.6x6) ≈ (5.5 or 7 or 8.3) ppl/second
Car occupancy is ~1.5ppl/car in the EU. Given that this is a german highway Average distance between cars ~3 lengths meaning 4x4.5m=18m/car. For a long time these roads had "no speed limit", but the recommendation was ~130kph. Let's conservatively use 120 & 100kph. This gives 1.5x3x(100 or 120)/(3.6x18) ≈ (7 or 8.3) ppl/second.
Various things fudge the numbers in either direction, but that's actually shockingly close between the two.
You don't enter or exit at 120kph so throughput is cut by the bottle neck of exiting/entering (also the reason why there's traffic no matter the number of lanes, bottleneck is the throughput of entry exit creates the traffic stall
Yeah I was trying to estimate the max throughput this highway has ever seen with cars, not the average. Nowadays they've even reduced the speed limit to a measly 80kph.
I gotta take issue with those numbers. A car moving at 130kph covers 18 meters in about half a second. According to the numbers I found online, experts estimate the perception-reaction time for braking at 1.5 seconds, which is up from the value of 0.75 seconds that they used to use. Thirteen and a half meters is an unrealistically-close following distance, even for German super-humans.
I have not driven on the Autobahn, but the videos I can find show scenes much more consistent with a ~55 meter (1.5 seconds) gap between cars, or much-slower traffic speeds. That drops the estimated human-throughput way, way down.
You assume people are driving safely - in my experience, during rush-hour at 90-100kph (Stockholm) someone will file in ahead of you if you leave more than 2 car lengths of space.
Is it safe? No.
Is it reality? Yes.
Furthermore, this is an estimate of a feasible max throughput that may have occurred.
Here is some data to get more accurate numbers:
The speed limit used to be higher though, originally it was nonexistent. Point was to estimate what the highest throughput of people in cars that highway has ever seen.
Point taken, you’re correct.
Ok, but still healthier for all.
And you can savely take half of car throughput on average. Or far less in congestion.
Just a fun calculation, aiming at comparing the video to a reasonable max throughput of people in cars that may have ocurred, not the average :)