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Comment by coolspot | Hacker News Reader

When roads belong exclusively to self-driving cars, they can increase speed, reduce gaps between cars and eliminate traffic wave effect.

Imagine highway where everyone drives 80mph with 5ft of distance between cars. No one suddenly changes lanes, no one suddenly slows down for no reason.

Here is illustration from Waymo testing facility: https://youtu.be/hKfEivMfDPU

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I believe you'd have better throughput by dedicating roads exclusively to buses and bicycles, which are technologies that already exist.

Local streets will always have pedestrians and cyclists. The main limit on road capacity is generally where highways interface with the local network, and the local network itself.

Also https://youtu.be/iHzzSao6ypE

Lol that is going to lead to the mother of all pile-ups not if but when something just so slightly goes wrong. Imagine somebody dropping shit from an overpass or really anything. Better build a giant cage over all the highways!

Those kind of pile ups already happen now when people drop crap from overpasses, how would it be any different?

because unless the driver is a raging asshole usually the person behind while you are going 80 has more stopping distance than 5 fucking feet.

That's because you're thinking of human drivers whom are so slow to react that it is recommended they keep a whopping 2 or 3 seconds [0] worth of trailing distance to respond to changing road conditions like the person in front of you slamming on their breaks. The hypothetical clustering of self driving cars requires them to react at much faster times so they don't need to keep as much space between them.

[0]: https://en.wikipedia.org/wiki/Two-second_rule

Bigger. Faster.

Even if there is no reaction time, 5' of space at 50mph is silly. You still need room to maneuver if whatever caused the vehicle ahead to throw on its breaks comes back or halts the vehicle ahead faster than your breaks can stop you.

It’s basically a virtual tandem semi. The presumption is that you are delegating command and control to the lead vehicle, and there is bidirectional communication between the lead and follow vehicles.

Well, why don't we go a step further then and physically connect the vehicles? Maybe we can also make them longer and fit more passengers? And we could optimize the rolling friction, replace rubber on tarmac with something better like steel on steel, and use some sort of tracks to provide the sideways forces?

You jest, but I'd love it if we could automatically group cars into physically connected trains for long distance travel, and have them automatically split off when they approach their destination. Maybe there's some way to do that with rails, carrying peoples' cars, but not sure if the efficiency gain is worth the increased complexity of including another set of wheels/motors/etc, and making the automated separation/joining work with all of that.

Are the other passengers quiet and housebroken? Does the steel track go to my office? (Broken or misused rail switches cause a lot of accidents.)

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