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> There were two main issues that had to do with following distance.

The trouble seems to be that they're being too conservative. Following distance is what it is because of human reaction times. You have to process the input with your brain, decide what to do, move your foot, then the car starts to slow down. In principle a computer can do it faster and so doesn't need as much space.

Moreover, everybody would like following distance to be dictated by safety, but in practice it's dictated by traffic volume. If you have traffic averaging three car lengths between each car and then twice as many cars merge into the highway, either you end up with one car length between each car, or you end up with stopped traffic. There is no third option.

The problem right now is that they're still using the human driver as a backup, so using the safe-for-computers following distance doesn't mesh with that, but using the safe-for-humans distance is a violation of standard behavior. So they're stuck choosing between the unsafe thing everybody does, or the "safe" thing that then becomes unsafe anyway because of how everyone else reacts to it.

I had the same issues in a Tesla. I adjusted the following distance down to dissuade people from jumping in front of me, but that felt even more unsafe. Seemed like there was no good solution.

The solution is to get people to stop being assholes on the road. Fine tailgaters. I care about the safety issues caused by them a lot more then I do about people going 6 over the limit.

Following any closer then 2 seconds of traveling distance on a clear, dry day, 3 seconds at night, or in the rain, 4 seconds on a rainy night should be considered reckless driving.

I feel like driving cars turns most people into idiots, myself included at times.

I don't have the citation, but I remember this quote:

"The easiest way to make people stupid is to limit their degrees of freedom"

Cars really only have 2 degrees of freedom: linear acceleration and radial acceleration. In traffic, these DoFs go down by a lot. You ability to de/accelerate linearly is very limited by the cars behind you and in front of you. Your turning also goes down to nearly a binary choice of 1 lane left/right.

Get people 4-wheeling and the stupid is very much still there, but just to get back to a main road, you have to use your noggin a fair bit more. Folks tend to think things through and weight choices more.

Are the horn and middle finger(s) not also degrees of freedom?

Actually, you make a good point.

The social dynamics are themselves a dimension. Social network graphs can behave as fractals. In a gymnasium filled with people, there is a significant 'fractallyness' to the social network. In traffic, the fractallyness is very limited to just about all the people in the road near you. The social graph, though more fluid in a traffic jam than a pep-rally, is still fairly small.

3Blue1Brown has a great video on the dimensionality of fractals [0] that is useful here. I'm just going to spitball, but I'd bet that the dimensionality of the social graph of a traffic jam is really close to 1.

So in the end, the DoFs of a traffic jam are probably very close to 3, but just a bit over. Say, 3.14-ish. ;)

[0] https://www.youtube.com/watch?v=gB9n2gHsHN4

The easiest way to solve this problem is to have serious standards from driving license tests. Have would be drivers perform reliably in a variety of conditions and in longer trips and mercilessly fail people who do not meet the high bar.

Rather than apply the brakes, barring the person jumping in front of you and braking, it could just stop applying the accelerator. Nice easy slowdown to create the gap without brake-jobbing somebody behind you.

Haven't driven a Tesla but I'm quite sure the safe braking distance is a lot shorter than it _feels_ like for a human and this is actually one of the tasks I'd rather leave to a computer than a human.

I'd assume the Tesla to have a lot better (quicker) reaction skills than you and you should probably just trust it (in this particular scenario) and relax, even though the distance might _feel_ too short.

Driving a Tesla for almost a year now and when I had mine for 2,5 weeks it crashed into a car in front of me on AutoPilot in slow moving traffic. Stop and go. After 15 stops, it moved again, but this time didn't stop. I just sat there expecting it would brake. It didn't. There was no major damage, just about $1500 due to a small dent in the hood. AutoPilot is beta. Don't trust it to be quicker than you. It will fail in ways humans do not ever expect. Always pay attention and take control if it feels off.

This is terrible. This is the exact reason why I would want to buy a Tesla. Just for the AutoPilot to drive the car in bumper-to-bumper freeway traffic. If it does not work reliably in this situation, then the AutoPilot is essentially worthless to me.

On my regular commute, the freeway interchanges that I must take, are too frequent, that I don't think the AutoPilot is worth the trouble to switch on. Especially when the freeway is empty, since I would have to take control of the car every few minutes.

The only scenario where I think AutoPilot is worth the effort to switch on, is if I must drive long distances on the same freeway, where you don't have to switch freeways. Like the drive from LA to SF. Or LA to Vegas. Or even just staying on the same freeway for 20 to 30 minutes.

I hope they can fix this deficiency. This AutoPilot technology is definitely beta, if they can't perfect simple stop-and-go freeway traffic.

I stand corrected.

It's weird because this really feels like one of the areas where technology could really excel in.

This is true, the car can panic stop very quicky. The problem is I want to leave enough space to dodge pot holes that the car in front of me just drove over, since Autopilot can't really do anything about that (nor do I expect it to)

I used a Honda Accord with a similar system and even had a similar experience to scenario 1 on the interstate (though I was set at 69). After I realized that the following distance control was the reason the car was going slower, I was initially fine with it, but then someone cut me off which then forced me to driving slower resulting in me turning off the system.

I have a feeling these systems won't really be great until all cars are using them and considering I don't see that happening, I don't see them gaining a ton of traction, unfortunately.

Don't cruise in the passing lane, that's bad form.

I wasn't? They passed on my left side?

My mistake. Yeah, people easing over from the left lane going slower than you or just in front of you is annoying. The only real way to combat this is to make them commit to going faster than you by speeding up, or going slower than you by keeping them boxed in. All in all, sounds possible like not great cruise conditions, which is pretty much all the time in most metro areas now.

We have a Honda with similar system. It can be annoying in heavy traffic, but wow is it amazing on long drives between cities. There's no more fighting the cruise control when you and the vehicle in ahead are a little out of sync speed wise - either due to 75mph being a little different in each or due to performance differences on hills.

On the whole, I find a 3+ hour drive a lot less stressful with the adaptive cruise control, and I arrive feeling much less fatigued.

The solution would be to detect attempts at cutting you off and automatically close the gap momentarily to discourage this behavior.

Ideally your autonomous car would also take part in the community of tailgaters and communicate forward that the current speed is unacceptable if this is the consensus of several tailgating vehicles, and gently reduce distance in a controlled way until the car in front gives in and speeds up or yields.

What you're describing is a car that eschews defensive driving in favor of offensive driving. Speeding up to keep people from cutting in front of you only works until the other driver doesn't see (or doesn't care) and now you're in a crash. Or traffic suddenly slows as you're speeding up to close the gap, and now you can't respond quickly enough and now you're in a crash. Letting someone cut you off and slowing to return to a safe following distance is by far the safer option.

There's a reason it's called a safe following distance. Anything closer and you cannot stop in time. Even temporarily. Especially when autonomous cars in front of you may be suddenly braking as well.

Safer from the minimizing personal liability perspective. If cutting people off is a valid tactic because they bend over and take it then more people will do it more of the time and that makes everyone less safe.

We don't negotiate with terrorists for a reason.

This is basically the opposite of the ideal solution.

The solution is to remove dangerous drivers from having control of 2-ton deathtraps, not contributing to the same behavior that is causing the problem.

Opportunistic, unsafe behavior is exactly the reason we need autonomous vehicles, rather than human-controlled vehicles.

Just give the user an up/down button and let them dial in the following distance themselves.

Or detect their preferred following distance for any given speed when the system isn't running and copy that.

Then you'll have AI engaging in unsafe driving habits because of their drivers and people will blame AI for every single accident rather than take responsibility.

Good way to get self-driving cars banned before they take off.

If the engineers allow the system to follow closer than is safe they should be personally liable for any accidents.

I wonder if we can't take all these advanced sensors for self-driving and use them to help LEO fairly detect unsafe driving in order to increase mean driver safety.

Ironically the parent was probably technically going over the speed limit, though everyone goes over the speed limit there. Whoever builds automated traffic violation software would need to be very fairhanded in order to not upset the status quo.

There is an Israeli startup that does this (using machine vision and freely issued iPhones to rideshare drivers; the name escapes me at the moment, I apologize) to provide data to insurance companies for better pricing of auto insurance rates.

I'm not sure I want to live in a future where my Tesla is a mobile sensor platform for someone else's benefit besides myself and Tesla, although I can see the allure of negating the need for LEO patrols on road infrastructure once a critical mass of sensor platform vehicles is reached in an area. This would require a herculean amount of governance and transparency to be okay with me, and I would expect more sanity in road legislation (higher reasonable top speeds, for example) as well.

Is it nexar? https://www.getnexar.com

Yes, thanks.

I'm in Hawaii RN and the speed limit on the interstate here is 45 - 55! It's bizarre world compared to bay area interstate driving.

The speed limit is irrelevant. What's the community accepted reasonable speed? I would wager that it's not much different than the same highway conditions elsewhere.

people drive the speed limit here. its a much different driving culture than the mainland and it helps that speeding is aggressively ticketed.

There's also the fact that there are only 4 Interstate highways in Hawaii totaling 54.9 miles, while in California, there are 25 Interstates totaling 2,455.7 miles. So, we've got more space to get up to speed ;) and, of course, longer distances to travel...

Why does it let you speed?

going 75-80 on I-80 isn't speeding. that's the pace of traffic even in the slow lanes. people do slow to like 70-75 if there is a highway patrol car nearby but since speed limits aren't really enforced 80 is the de-facto limit. and since cars are no longer the greatest cause of death in the US, they gotta let it go to cull the herd a bit and get that death rate up. (/s)