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>Safe following distance isn't predicated on defying physics, it means assume the car in front might stop dead for any reason No, it's based on assuming the ca

>Safe following distance isn't predicated on defying physics, it means assume the car in front might stop dead for any reason No, it's based on assuming the car in front might brake at standard non-physics-defying rates at any time. The 'safe' following distances that are advised don't allow for encountering stationary objects. That's why they're called following distances, as in, you're following another vehicle that obeys the laws of physics.

alistairSH 5y ago
But that Tesla didn't defy physics. Nor did it fall out of the sky. It braked and slowed like any other car. Maybe there truly wasn't enough time to completely avoid a crash. But there should have been enough time to avoid a serious (deadly) crash.
- Lascaille 5y ago
  >It braked and slowed like any other car. Imagine you're following - at a safe distance - a vehicle. The driver of the vehicle you're following doesn't notice that the car ahead of them is emergency braking. They notice at the last second and swerve around it to avoid a collision. You are then face to face with a nearly-stationary object which was concealed from you by the vehicle ahead of you. From your perspective, it fell from the sky. If you don't swerve, a collision is unavoidable.
  - cameronh90 5y ago
    I think we are in agreement with the the situation, I just disagree and think you're either driving too fast or following too close. Your logic leads to pile ups, as in the event of a pile up, a car stops dead unexpectedly infront of you and you have nowhere to swerve. I can't speak for the USA, but in the UK, if someone swerves and you rear end a stationary object, you are at fault. Indeed if you rear end another vehicle, you are nearly always at fault (unless e.g. they pulled in front of you then immediately slammed the brakes). For stopping distances, this is what we are taught in the UK (rule 126): https://www.gov.uk/guidance/the-highway-code/general-rules-techniques-and-advice-for-all-drivers-and-riders-103-to-158 https://www.gov.uk/guidance/the-highway-code/general-rules-t... Stopping distance at 70mph is about 100m and "The safe rule is never to get closer than the overall stopping distance". This is a minimum - in adverse conditions the distance should be even greater. This means when you see the stationary object, you're about 100m away, which is adequate time to stop IF you're paying attention and your car is well maintained (we have annual MOTs to ensure this).
cameronh90 5y ago
I don't know about the USA, but in the UK our stopping distances assume the car might become stationary at any point. That is, they are actually stopping distances - not following distances. If you follow closer than that on your test, you will fail.

alistairSH 5y ago

But that Tesla didn't defy physics. Nor did it fall out of the sky. It braked and slowed like any other car. Maybe there truly wasn't enough time to completely avoid a crash. But there should have been enough time to avoid a serious (deadly) crash.

Lascaille 5y ago
>It braked and slowed like any other car. Imagine you're following - at a safe distance - a vehicle. The driver of the vehicle you're following doesn't notice that the car ahead of them is emergency braking. They notice at the last second and swerve around it to avoid a collision. You are then face to face with a nearly-stationary object which was concealed from you by the vehicle ahead of you. From your perspective, it fell from the sky. If you don't swerve, a collision is unavoidable.
- cameronh90 5y ago
  I think we are in agreement with the the situation, I just disagree and think you're either driving too fast or following too close. Your logic leads to pile ups, as in the event of a pile up, a car stops dead unexpectedly infront of you and you have nowhere to swerve. I can't speak for the USA, but in the UK, if someone swerves and you rear end a stationary object, you are at fault. Indeed if you rear end another vehicle, you are nearly always at fault (unless e.g. they pulled in front of you then immediately slammed the brakes). For stopping distances, this is what we are taught in the UK (rule 126): https://www.gov.uk/guidance/the-highway-code/general-rules-techniques-and-advice-for-all-drivers-and-riders-103-to-158 https://www.gov.uk/guidance/the-highway-code/general-rules-t... Stopping distance at 70mph is about 100m and "The safe rule is never to get closer than the overall stopping distance". This is a minimum - in adverse conditions the distance should be even greater. This means when you see the stationary object, you're about 100m away, which is adequate time to stop IF you're paying attention and your car is well maintained (we have annual MOTs to ensure this).

cameronh90 5y ago

I don't know about the USA, but in the UK our stopping distances assume the car might become stationary at any point. That is, they are actually stopping distances - not following distances. If you follow closer than that on your test, you will fail.