3 ms·

It takes humans up to 5 seconds to even start breaking in the presence of danger. Even at 40 miles per hour your speed is 58 feet per second (or, at 60kmh you

It takes humans up to 5 seconds to even start breaking in the presence of danger. Even at 40 miles per hour your speed is 58 feet per second (or, at 60kmh you speed is 16 meters per second). So it's either "the driver had sufficient warning" or "the lane change from Tesla was dangerous". As you don't expect cars that are dangerously changing to suddenly slow down.

jiriro 4y ago
5 seconds is nonsense. The average driver’s reaction time is 0.2 to 0.3 seconds. This is before the driver’s foot moves. Then there is approx 1 second before the brakes take effect (foot movement, applying the force, brakes responding) So 1.5 second before the car starts breaking. There is a rule of “be at least 2 seconds behind the car in front” which gives a safe distance to handle any emergency braking. Of course everything depends on driver’s and car’s conditions.
- dmitriid 4y ago
  Sweden has the rule of "at least 3 seconds". Because you keep ignoring the speed, and the braking distance as well. Edit: and assuming perfect conditions when the driver is perfectly alert and looking ahead. And is young and healthy. And... However you count, if Tesla did a dangerous lane change and started braking, how is this the fault if the driver behind?
  - AmericanChopper 4y ago
    You seem to be missing a couple of point here. 1. Fault in an accident can be spread across every party that was involved, and no matter how negligent one part was, that has no influence over how negligent every other party also potentially was. 2. A driver is typically responsible for being aware of all potential hazards on the road, not just the ones immediately ahead in the same lane. For instance a car that has started indicating to move into their lane from another lane (as this Tesla did ~7 seconds before the collision), and a car in their lane that is coming to a stop (this Tesla had completed the lane change pretty much 3 seconds before the collision). Obviously the Tesla is really pushing the limits of what would be considered a safe gap, and coming to a stop in that location without a proper reason is obviously negligently dangerous. But the negligence of both parties contributed to this accident, regardless of who was most at fault.
- smaudet 4y ago
  It's absolutely not nonsense, I suggest taking some basic high-school physics. Reaction time is the time for the vehicle to come to a stop, not for the driver to first notice an issue. At 60 mph it will take many meters and seconds to deaccelerate, assuming the driver can take exactly the correct action: https://www.wolframalpha.com/input?i=time+to+brake+at+70+meters https://www.wolframalpha.com/input?i=time+to+brake+at+70+met... Estimate here is about 4 seconds, under perfect conditions. 5 seconds is more than reasonable, considering you also need to realize the other driver is acting erroneously.
  - frumper 4y ago
    he said 5 seconds to START braking
    - smaudet 4y ago
      I did not interpret their comment that way. That would be unreasonable, however their comment included mention of physical break distance, so I'm pretty certain they didn't mean actual human response time and instead how long it takes for a human to respond and slow the car, which is the metric of interest here. Even for a robot with millisecond response times, you will be breaking in the multiples of seconds, not instantaneously. Observation "reaction time" really is completely irrelevant here.
      - frumper 4y ago
        > It takes humans up to 5 seconds to even start breaking in the presence of danger. That seems pretty clear. 5 total seconds is really reasonable. 5 seconds before you start is silly.
  - mikestew 4y ago
    Reaction time is the time for the vehicle to come to a stop You seem to have your terminology confused. Reaction time doesn’t even necessarily have anything to do with driving. I suggest a quick web search next time before assigning people remedial physics.
meindnoch 4y ago
5 seconds?? Lol. Maybe if the driver is 86 years old.

jiriro 4y ago

5 seconds is nonsense. The average driver’s reaction time is 0.2 to 0.3 seconds. This is before the driver’s foot moves. Then there is approx 1 second before the brakes take effect (foot movement, applying the force, brakes responding) So 1.5 second before the car starts breaking. There is a rule of “be at least 2 seconds behind the car in front” which gives a safe distance to handle any emergency braking. Of course everything depends on driver’s and car’s conditions.

dmitriid 4y ago
Sweden has the rule of "at least 3 seconds". Because you keep ignoring the speed, and the braking distance as well. Edit: and assuming perfect conditions when the driver is perfectly alert and looking ahead. And is young and healthy. And... However you count, if Tesla did a dangerous lane change and started braking, how is this the fault if the driver behind?
- AmericanChopper 4y ago
  You seem to be missing a couple of point here. 1. Fault in an accident can be spread across every party that was involved, and no matter how negligent one part was, that has no influence over how negligent every other party also potentially was. 2. A driver is typically responsible for being aware of all potential hazards on the road, not just the ones immediately ahead in the same lane. For instance a car that has started indicating to move into their lane from another lane (as this Tesla did ~7 seconds before the collision), and a car in their lane that is coming to a stop (this Tesla had completed the lane change pretty much 3 seconds before the collision). Obviously the Tesla is really pushing the limits of what would be considered a safe gap, and coming to a stop in that location without a proper reason is obviously negligently dangerous. But the negligence of both parties contributed to this accident, regardless of who was most at fault.
smaudet 4y ago
It's absolutely not nonsense, I suggest taking some basic high-school physics. Reaction time is the time for the vehicle to come to a stop, not for the driver to first notice an issue. At 60 mph it will take many meters and seconds to deaccelerate, assuming the driver can take exactly the correct action: https://www.wolframalpha.com/input?i=time+to+brake+at+70+meters https://www.wolframalpha.com/input?i=time+to+brake+at+70+met... Estimate here is about 4 seconds, under perfect conditions. 5 seconds is more than reasonable, considering you also need to realize the other driver is acting erroneously.
- frumper 4y ago
  he said 5 seconds to START braking
  - smaudet 4y ago
    I did not interpret their comment that way. That would be unreasonable, however their comment included mention of physical break distance, so I'm pretty certain they didn't mean actual human response time and instead how long it takes for a human to respond and slow the car, which is the metric of interest here. Even for a robot with millisecond response times, you will be breaking in the multiples of seconds, not instantaneously. Observation "reaction time" really is completely irrelevant here.
    - frumper 4y ago
      > It takes humans up to 5 seconds to even start breaking in the presence of danger. That seems pretty clear. 5 total seconds is really reasonable. 5 seconds before you start is silly.
- mikestew 4y ago
  Reaction time is the time for the vehicle to come to a stop You seem to have your terminology confused. Reaction time doesn’t even necessarily have anything to do with driving. I suggest a quick web search next time before assigning people remedial physics.

meindnoch 4y ago

5 seconds?? Lol. Maybe if the driver is 86 years old.