> every other car could slam on their brakes at any time

Or veer out of the way of an obstacle you can't see, leaving you to either similarly veer or collide with it. IOW, do not assume you only need to account for your own reaction time; rather assume the vehicle in front of you can instantly stop moving and you must account for both your reaction time and your vehicle's stopping distance.

Your safety advice is completely unreasonable to follow on highways. When you give that sorta advice, you make safety worse not better.

It takes about a 100 yards -- a full football field -- for a normal passenger car to react and come to a complete stop.

https://www.qld.gov.au/transport/safety/road-safety/driving-...

This is equivalent to 4 full seconds of following distance, which is double the typical 2-second-rule recommended by transportation governing bodies.

https://en.wikipedia.org/wiki/Two-second_rule

If your suggestion was taken seriously, it would literally halve the carrying capacity of our highways.

Luckily, situations where the vehicle in front of you comes to an instantaneous stop are extraordinarily rare, basically requiring a head-on collision.

From your own link:

> The two-second rule tells a defensive driver the minimum distance needed to reduce the risk of collision under ideal driving conditions. The allotted two-seconds is a safety buffer, to allow the following driver time to respond. [emphasis mine]

> Some authorities regard two seconds as inadequate, and recommend a three-second rule. […] The United States National Safety Council suggests that a three-second rule—with increases of one second per factor of driving difficulty—is more appropriate. Factors that make driving more difficult include poor lighting conditions (dawn and dusk are the most common); inclement weather (ice, rain, snow, fog, etc.), adverse traffic mix (heavy vehicles, slow vehicles, impaired drivers, pedestrians, bicyclists, etc.), and personal condition (fatigue, sleepiness, drug-related loss of response time, distracting thoughts, etc.). For example, a fatigued driver piloting a car in rainy weather at dusk would do well to observe a six-second following distance, rather than the basic three-second gap.

I've had to veer to avoid accidents. At least three sitautions I can remember on the interstate: a semi truck tire blowout in front of me leaving large parts of the tire in my lane; a bike rack with several bikes falling off the back of a car in front of me; a truck in front of me veering around a obstacle (it appeared to be a pickup truck bed liner) I was blind to because I couldn't see beyond the truck in front of me.

I was lucky to avoid all of these because I had a parallel lane or shoulder I could escape into. When I drive now, if it's congested I leave extra following diatance. If that reduces the road capacity so be it. Compared to drivers who follow much too closely (which itself causes sudden slowdowns since they tend to over brake) or who drive in the wrong lane for their speed, I don't think I'm the person you need to worry about.

FWIW, I haven't been in an accident in over 25 years.

Nowhere on my link does anyone recommend a general 4-second rule, and this doesn't even account for the fact that we should expect safety organizations to err on the side of too much safety. Note that your recommendation is specifically not a tailored approach designed to adjust to risky situations, but rather a fixed criteria.

Your strategy to take all possible precautions regardless of large efficiency loss doesn't align with the reasonable tradeoffs that the vast majority of humans make.

I disagree. On a congested road, If you can't see two cars ahead of you and react to the actions of that second car, you're not driving safely.

On a non-congested road, there's no excuse for putting sufficient distance between you and the car in front.

Your recommendation on non-congested roads is vague and I don't think your recommendation for congested roads conflicts with my critique of js2. Certainly, it's often impossible to see 200 yards ahead on various stretches of the highway, so any reasonable driver will be violating js2's advice if they follow yours.

If you think putting sufficient distance between you and the car in front is vague, you are a poorly educated driver and most likely a dangerous one.

If you can't see 200 yards ahead, you should not be travelling at a speed which precludes you from stopping within 200 yards.

On a single lane uncongested road, there's no excuse for putting a reasonable (at least 3 second) gap between you and the vehicle in front.

> If you think putting sufficient distance between you and the car in front is vague, you are a poorly educated driver and most likely a dangerous one.

Huh? The whole context of this discussion starting from js2's comment is about exactly how far is should be, and in particular whether 2 seconds or 4 seconds (which at highway speeds is 50 yards vs. 100 yards) is more reasonable as a rule of thumb. As you can see from my link, most government safety organizations recommend 2 or 3 seconds in good weather.

A well known insurance scam is changing lanes immediately in front of another car then coming to a sudden stop, forcing a rear end collision. It's hard to prove unless you have a dash cam and even then you might be found at fault if the other party is convincing enough to the officer who investigates the accident.

> A well known insurance scam is changing lanes immediately in front of another car then coming to a sudden stop, forcing a rear end collision.

It's an even more brilliant way to defend barely-working robot cars. Program them to err toward the letter of the law rather than road safety, then blame other drivers when they slam on their brakes because they mistake plastic bags for pedestrians.

> If you rear-end a vehicle that's established in your lane, it's always your own fault, no exceptions.

Of course there are exceptions. There are any number of well-established circumstances that, if proven, place responsibility on the driver in front.

It is not legal to suddenly panic-brake to a stop, for instance, without exigent circumstances which make it necessary to do so. If a driver causes a collision by doing so they bear liability. There are any number of insurance scams that are thwarted by such exceptions.

Citation? I haven't been able to find any instance where this is true except where the driver was found to have braked suddenly with the intent to cause an accident, which would clearly not have been the case with a self-driving car.

Are you saying brake checking a tailgater is not illegal? It is the persons fault for not rear ending a vehicle, its also the first drivers responsibility to drive responsibly (i.e. not braking or stopping for things that are imaginary)

Similar to how being an asshole and flipping someone off while driving is not illegal, or how being an asshole and tailgating someone is not illegal, brake checking a tailgater certainly makes you an asshole, but it is not illegal.

Social responsibility be damned.

It is illegal in many states under 'aggressive driving' or 'road rage'.

Feel free to feel smug whole dying in a ditch by the side of a road. Or you know maintain a reasonable following distance so sudden stops are a non issue...

Really, when it's ego vs several tons at highway speeds it's not ego that wins. Further, 'I thought I saw something' is a blanket exception for sudden breaking.

Im just saying self driving cars should be required to drive within a reasonable expectation of a normal, safe, predicable manner. If they are not there yet, maybe they shouldn't be on the roads yet.

They are. If this was about sudden evasive manovers and lane changes then sure, but simply breaking more frequently is a non issue because again any car can break at any time and you need to deal with such reasonable and normal behavior.

Based on the number of comments from people that live in these town I do not believe this is simply more frequent braking. It sounds like it happen a lot and unnecessarily, which adds risk and frustration to humans also using the road.

People are more likely to notice and remember self driving cars, so you can't assume they are accurately reporting frequency vs. just remember more frequently and or a biased sample.

...someone brake checking is the one running on ego. And they're the one likely to get hit despite being "technically correct".

If someone is dangerously tailgating me, I will very lightly brake-check them (barely slowing down) because the vast majority of tailgaters seem to be mediocre drivers who aren't thinking deeply about their actions. If they persist, I'll slow down and let them overtake.

When I'm driving, I'm constantly scanning for bad (i.e. unsafe or unpredictable) drivers in all directions. Once spotted, the choice is either to be well past them or well behind them. Usually the choice is easy.

Tailgating is a sign of gross incompetence. I never said you should break check, but if your going to have an accident it's better to be rear ended than hit something and then been rear ended with a much larger speed differential.

PS: Tail gaters are creating a highly dangerous situation so slowing down without jamming the breaks is the correct response.

I've been rear-ended a couple of times. In all cases, I talked to their insurance and said, "They had the responsibility to maintain a safe driving distance, it doesn't matter what I did, they can't rear end me," and that has been an argument that has always completely worked: they've always taken full responsibility for the accident.

(To be clear, I wasn't intentionally provoking anything: in one case I hit my brakes because the car in front of me panic-stopped, in another I was in a right-turn-yield-into-another lane situation and I checked my blindspot and found that there was a car who had right-of-way, so I hit my brakes to keep from encroaching on them.)

My car got rear ended in the snow. It was parked outside my house and I was in bed at the time.

It was a good couple of months before they took responsibility for the accident.

i believe "right-turn-yield-into-another lane" is forbidden in man places for this reason, although I might have misunderstood you.

I think you probably did. I was making a right turn at a controlled intersection. Specifically, the dedicated right turn lane was controlled by a yield sign. I had slowed and was preparing to merge into the other lane, checked my blind spot over my shoulder, and found that there was a car in my blind spot, so I braked to let it pass me (since the yield sign gave it right of way). The car behind me failed to react to my breaking and rear-ended me.

> It is the persons fault for not rear ending a vehicle, its also the first drivers responsibility to drive responsibly (i.e. not braking or stopping for things that are imaginary)

Pitch this line to your insurance company if you ever end up causing a rear ending. It'll be entertaining for the rest of us at least.

Doesn't matter what the car in front of you is up to or not. If you do not leave enough space to be able to handle them stopping, you are at fault. You should be utilizing defensive driving, and not depending on the driver in front of you ever acting responsibly or rationally.

You will be liable but the first driver has a responsibility to drive responsibly. Stopping for no reason and causing an accident should be considered aggressive driving and in many states is illegal.

How do you propose I tell the difference between something I imagine seeing and something that is really there? In both cases there's an observable phenomenon, and it is only though collision with the imagined object that I can tell the difference.

If I think I see a child in the road I'm sure as hell not going to stop and wonder if I'm just imagining it before I brake.

He didn't cause an accident, though. If you crashed into him, you were too close and caused the collision.

It's not about intent, it's about behavior.

Your insurance carrier will not care what the other driver should have been doing, if you rear end someone you are at FAULT as you failed to keep a safe distance from the car in front of you. It doesn't matter if they slow or stop for any reason ahead of you, if you run into them it's your fault.

> "For purposes of insurance and policing, the driver of the car that rear-ends the other car is almost always considered to be at fault due to not leaving enough stopping distance or lack of attention." [1]

I'm glad we have drivers on the road that hope for the best in other drivers, but you need to sink this in your head today:

You should treat everyone on the road as an accident waiting to happen, and should practice defensive driving at all times in response.

[1] https://en.wikipedia.org/wiki/Rear-end_collision

I might need to slam on the brakes at any moment because a child or deer or something ran onto the road. You always have the obligation to maintain a safe stopping distance. No exceptions.

Stopping for something imaginary and brake-checking a tailgater are not the same thing. Another person's irresponsibility does not justify your own. Your responsibility does not change based on your value judgement of another person's actions.

Braking with the intention to cause an accident is illegal in some places. I can't find any law making it illegal to suddenly brake because you mistakenly believe that it is necessary to do so.