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> There is no single definition of tailgaiting other than being able to not being able to stop at a reasonable distance. So it is impossible to declare what con

by shkkmo 3y ago

> There is no single definition of tailgaiting other than being able to not being able to stop at a reasonable distance. So it is impossible to declare what constitutes tailing, especially in the mixed case of human drivers and robot drivers (who have a reputation for nuisance braking). What is this nonsense? The safe following distance is determined by how fast you can stop, not by who is driving the vehicle you are following. > Why, for example, do you think trainers post "Student Driver" stickers on their cars? It's because it signals the driver may be more unpredictable. No, it signals they have less experience and are more dangerous drivers. When it comes to driver predictability, student drivers tend to be far more predictable than the adult, overconfident drivers. I've never seen a student driver roaring past me in stopped traffic on a shoulder, or floor the gas to pass me through a light because they didn't want to turn in a turn only lane, or any of the other unpredictable things I see on a regular basis from experienced drivers. > You're essentially advocating that everyone treat everyone else (and every robot) as a student driver. That's fine for a dichotomous safety mindset, but other people would prefer to recognize the tradeoffs with that approach. I think that if more driver treated the people around them as student drivers, our roads would be a lot safer. I know that if people followed at a safe distance then we would have fewer traffic jams. Edit: You also seem stuck on the idea that Waymo unsafely unexpectedly brakes more often than human drivers, yet that isn't clear to me from the data we have. Indeed it seems like the opposite is true from the data.

bumby 3y ago
>The safe following distance is determined by how fast you can stop, not by who is driving the vehicle you are following. So when you're driving, do you somehow know the braking distance of every car and reaction time of every driver around you? You don't, and since their braking distance is needed to know your own braking requirements, you have to use heuristics. Maybe your heuristic is "assume everyone will cram on the brake, full tilt, at any time." But, that is not a pragmatic solution given our current infrastructure. We don't have the road capacity for everyone to drive that way. So we make tradeoffs. Part of that tradeoff means anticipating what other drivers will do and adjusting accordingly. Naturally, this will trade some safety for other things we value. That is the reality of the world we live in. You seem to be advocating for something else. The OP was that we might struggle to apply such heuristics without a theory of mind to guide us. We probably just disagree on the student driver vs. overconfident drivers. I feel like I'm pretty good at anticipating aggressive drivers, and I fear them must less than the super-tentative driver that tends to put other people at risk. But unless you have data, we're just talking about subjective opinion here so it's not really worth delving into further. >I think that if more driver treated the people around them as student drivers, our roads would be a lot safer. Sure. But again, it doesn't really fit with the world we live in. Should we all, in general, drive more defensively? Sure. But I doubt our infrastructure will allow for 25+ car lengths between vehicles that the NHTSA recommends, so we're stuck making some tradeoffs. I agree on the data point. I'm not making strong claims about safety. I'm making claims about uncertainty. One thing that is clear (and I've advocated elsewhere) is that we don't have good data (in part, because companies get to share only what they want in many cases), which makes uncertainty greater.
- throwaway2037 3y ago
  25+ car lengths between vehicles that the NHTSA recommends Is this hyperbole? I tried to Google for it, but I could not. The best I could find was the three second rule. Some back-of-the-envelope calcs: Length of Honda Accord (according to Google): 192 inches. 75 miles per hour / 60 minutes per hour / 60 seconds per minute * 5280 feet per mile * 12 inches per foot * 3 seconds / 192 inches = 20.625 car lengths. Even three seconds isn't enough to reach your recommendation of 25+ car lengths. Note: 75 mph is 120 kmh
  - bombcar 3y ago
    The actual calculation involves how fast the vehicle you’re following can decelerate, and your reaction time. You can (usually) follow a large semi a bit closer because its braking distance is longer than yours. But because of reduced visibility you can end up with “revealed brake checkmate” where the semi swerves into the next lane because a vehicle is stopped in the lane, which you then need to swerve or hit.
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  - bumby 3y ago
    They recommend estimating 4.5 seconds of stopping distance. But that’s very conservative and probably not realistic.
    - throw10920 3y ago
      That's ridiculous. There's nothing "unrealistic" about 4.5 seconds of stopping distance - how could there be, are you thinking that the highways physically wouldn't fit all the cars spaced at that length?

by shkkmo 3y ago

bumby 3y ago

>The safe following distance is determined by how fast you can stop, not by who is driving the vehicle you are following. So when you're driving, do you somehow know the braking distance of every car and reaction time of every driver around you? You don't, and since their braking distance is needed to know your own braking requirements, you have to use heuristics. Maybe your heuristic is "assume everyone will cram on the brake, full tilt, at any time." But, that is not a pragmatic solution given our current infrastructure. We don't have the road capacity for everyone to drive that way. So we make tradeoffs. Part of that tradeoff means anticipating what other drivers will do and adjusting accordingly. Naturally, this will trade some safety for other things we value. That is the reality of the world we live in. You seem to be advocating for something else. The OP was that we might struggle to apply such heuristics without a theory of mind to guide us. We probably just disagree on the student driver vs. overconfident drivers. I feel like I'm pretty good at anticipating aggressive drivers, and I fear them must less than the super-tentative driver that tends to put other people at risk. But unless you have data, we're just talking about subjective opinion here so it's not really worth delving into further. >I think that if more driver treated the people around them as student drivers, our roads would be a lot safer. Sure. But again, it doesn't really fit with the world we live in. Should we all, in general, drive more defensively? Sure. But I doubt our infrastructure will allow for 25+ car lengths between vehicles that the NHTSA recommends, so we're stuck making some tradeoffs. I agree on the data point. I'm not making strong claims about safety. I'm making claims about uncertainty. One thing that is clear (and I've advocated elsewhere) is that we don't have good data (in part, because companies get to share only what they want in many cases), which makes uncertainty greater.

throwaway2037 3y ago
25+ car lengths between vehicles that the NHTSA recommends Is this hyperbole? I tried to Google for it, but I could not. The best I could find was the three second rule. Some back-of-the-envelope calcs: Length of Honda Accord (according to Google): 192 inches. 75 miles per hour / 60 minutes per hour / 60 seconds per minute * 5280 feet per mile * 12 inches per foot * 3 seconds / 192 inches = 20.625 car lengths. Even three seconds isn't enough to reach your recommendation of 25+ car lengths. Note: 75 mph is 120 kmh
- bombcar 3y ago
  The actual calculation involves how fast the vehicle you’re following can decelerate, and your reaction time. You can (usually) follow a large semi a bit closer because its braking distance is longer than yours. But because of reduced visibility you can end up with “revealed brake checkmate” where the semi swerves into the next lane because a vehicle is stopped in the lane, which you then need to swerve or hit.
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- bumby 3y ago
  They recommend estimating 4.5 seconds of stopping distance. But that’s very conservative and probably not realistic.
  - throw10920 3y ago
    That's ridiculous. There's nothing "unrealistic" about 4.5 seconds of stopping distance - how could there be, are you thinking that the highways physically wouldn't fit all the cars spaced at that length?