This is sad, but it's worth noting that even with a human driver, a car that stops suddenly is not responsible for any subsequent rear end collision(s). The colliding driver has the responsibility to keep a safe stopping distance at all times.
It's totally reasonable. It's not hard to maintain a safe following distance. Sudden braking isn't the only reason to do so, and insurance claims aren't the only motivating factor. You drive defensively so as to reduce the likelihood of death and destruction while making life easier for other drivers.
So if a car swerves into your lane 10 meters in front of you, then slams on the brakes, you're at fault because it should have been so easy to maintain a safe following distance? (This isn't hypothetical, I've had this exact scenario happen multiple times -- on/off ramps seem to bring out the worst in some drivers).
Whether or not it's reasonable is immaterial. If you constantly consider the possibility of the cars around you to do something unexpected, then you're more likely to avoid death and destruction. As well as prevent the death and destruction of the people around you. It's called defensive driving.
Maybe it's unfair, or too much to ask, or just too difficult. But it's reality.
I'm rooting for self driving cars because I believe that, theoretically, they'll do a much better job than people. In the long run.
However, today, you have to pay attention or you might die. And even if you pay attention you still might die.
My dad told me a story about a coworker he had who was in a car accident. He was sitting at a long line in the highway at a tollbooth. It was foggy. My dad's coworker was watching the fog behind him like a hawk because he didn't feel safe just sitting completely stopped in the highway. A semi-truck appeared out of the fog moving at high speed. My dad's coworker cranked his steering wheel and tried to accelerate off to the side of the road but got rear ended by the truck. He was lucky. Because he was already headed away, this car got bumped out into a field. His car was destroyed and he got a bunch of injuries, but he lived. The people in front of him in the line were not lucky. A bunch of them died.
It's not fair or reasonable. But being constantly considering possibilities saved this guy's life. The other people are dead.
The willingness of so-called intelligent beings to needlessly risk their lives (and the lives of those around them) for no gain whatsoever is truly astounding.
Road capacity is a function of number of lanes, the velocity of the vehicles traveling in those lanes, and the density of the vehicles traveling in those lanes. If you reduce the latter, you reduce road capacity.
Theoretically, everyone would be safer if they drove far enough back from the front of the car to come to be able to come to a full stop. Practically, the political uproar of enforcing this would be untenable, but I would be entertained to see the forthcoming overpopulation vs pave over all the land with roads vs mass transit vs variable rate tolling conversations that ensue.
> Road capacity is a function of number of lanes, the velocity of the vehicles traveling in those lanes, and the density of the vehicles traveling in those lanes. If you reduce the latter, you reduce road capacity.
And yet study after study shows that increasing the number of traffic lanes only worsens congestion.
If you have 10 cars wanting to use a stretch of road capable of carrying 10 cars at 8AM at speed X with the safest distance gaps, and you add 10 more cars, then there will be some combination of congestion behind this stretch of road, the distance gaps getting smaller, or cars driving faster now that there are 20 cars.
If you add a lane so that 20 cars can travel at the safest driving distance gaps at 8AM at speed X, but this then causes 10 more cars to come on the road because they see the possibility of using a road that is maybe just under maximum capacity, then you now have 30 cars on a 20 capacity road, and once again you end up with previous situation as 20 cars on a 10 car capacity road.
Obviously these things are impossible to exactly predict and constantly in flux and so engineers and politicians and drivers are all crudely estimating the shifts of supply and demand curves, and the overestimating and underestimating will cause congestion, or complaints of excess road, etc.
I should add this my near daily experience driving to my office in a rural area at 5am when there is just me and a random car behind me. With 2 miles or more of empty road behind him.
I anticipated this response, hence I tried to pre empt it by making my first qualifier that I am not talking about tailgating 2cm from the car in front.
> If people drove such that they had enough stopping distance to come to a full stop on highway at 65+mph,
This qualifying statement was supposed to convey that the theoretical safest distance to travel behind someone at 65mph, 75mph, or more is so big that I would not expect it to be followed anytime other than the dead of night.
You can actually avoid a collision at moderate speed by simply giving your brain time to react to events happening in front of you. And, even if you do hit something, doing so at a moderately low speed may not turn out so bad?
I can think of quite a few chokepoints in the US (Manhattan/SF-San Jose/LA/Seattle/Austin) where no matter what you do, the crush of cars will be too much for the roads that exist.
In these cases though, I think public transit is the only real solution, but that is a different topic.
Absolutely correct. It is then your responsibility to put a safe stopping distance between yourself and _that_ car.
You are in a death machine surrounded by other death machines. Sometimes you have to choose the less convinent option.
Neither would seem to apply to an automated system that randomly stomps on the brakes. I would think a system like that might affect fault on the civil, rather than criminal, side, however. For example, it would seem a bit mad for the insurance companies not to blame the vehicle whose screwy brakes caused a multi-car accident.
It's completely different to drive behind a vehicle going at 100 km/h on a empty, well maintained (yeah, 3rd world where I live has this variable too), straight, ascending, dry road; vs behind a sinuous route downhill on a mountain, with less lanes, under some weather condition, etc.
If a car in front of me SLAMS the breaks in the first scenario, I'm certainly not responsible for not being 3km away from him. In the second? Totally different.
"Safe stopping distance" is not a fixed number. And I doubt any car can properly calculate that because there's just too much context to be accounted for.
At least 2-3 seconds, minimum. Did you not take any driver's ed classes?
>Enough to react to the vehicle in front of you slamming the breaks at what speed?
Time, not speed. It will take the average person around 1.5 seconds to react, and a car at least a second to break. Time is not hard regardless of distance, you can see when somebody in front of you passes literally anything, a sign, a tree, a rock, a road market, whatever, then just count. FFS.
>If a car in front of me SLAMS the breaks in the first scenario, I'm certainly not responsible for not being 3km away from him
Not responsible for being 3000m away? Sure. ABSOLUTELY RESPONSIBLE for not being 50-80m way? Yes. Both legally and morally. Maintaining at least 2-3 seconds of distance just isn't a big fucking ask. And yes that's just as true if it's an "empty, well maintained" road, well why the fuck are you tailgating in that case? Shit happens. Animals suddenly leap across the road, a pothole has opened up, someone has collapsed in weird places etc. I literally was walking with a friend along an empty straight road in a rural area a few weeks ago and they suddenly just blacked out while walking and collapsed directly into the road. Scared the crap out of me. They'd had a pulmonary embolism not too long ago and their lung function was badly affected and while they're trying to build back up sometimes they just... black out. And if you're in a car you won't see someone lying down until you're fairly close. Low probability event? Absolutely. But over hundreds of millions of people it happens.
People sometimes need to stop as fast as possible. It is in every single way your job not to rear end them if they do. Period.
People don't operate like that. Sometimes, if you keep that distance all the times like you're saying you'll end up putting yourself and other people in danger, just because you're the only one thinking like that. I've had my fair share of furious truck drivers cutting me at high speeds in terrible situations at night, while our baby is crying in the backseat, his mother is exhausted and we can't find a single spot to stop and breathe before progressing. It has happened during the day on empty roads too. I've been in danger for acting like that while everyone else doesn't expect me to. Just like the safe-break assistant in this situation.
GP is right, though, it is highly context dependent. If you are following another car and paying attention, then two seconds is enough if they slam on the brakes. There is an implicit assumption that two cars have roughly equivalent braking ability.
But what if they do some sort of assisted stop? Bridge abutment. Head-on collision. Or what if there is a stopped car in front of the car in front of you, and the car in front of you swerves out of the way leaving you bearing down on an unexpectedly stopped car in the lane? 3 seconds won't be enough.
I still remember vividly many years ago coming around a high speed sweeping corner behind another car, at a perfectly reasonable stopping distance, and then they jerked the wheel into the oncoming lane and suddenly I was facing the back of a stopped car. That was exciting. I did not hit the car, but it was close, very close. The only way to avoid that is a stopping distance much greater than 2-3 seconds.
If people truely cannot calculate this, we shouldn't have cars.
Personally I know my car quite well and its stopping distance in most conditions. I always operate it further than the stopping distance. If I couldn't, I wouldn't drive. It's not worth the risk for myself or anyone else.
However if you don't know the basics of knife safety (you shouldn't throw them, they're sharp, etc), maybe you shouldn't operate one.