3 ms·

For exactly the reason you list, what you describe is not a "safe following distance."

by kd5bjo 9y ago

PuffinBlue 9y ago
You can argue the point until blue in the face but you're not going to improve anyones safety by chasing this argument. Humans are terrible at managing risk. Humans will always make mistakes. Telling them to 'not follow closely' is futile. If you don't design systems to take account of this then your safety practices will be ineffective. If autonomous systems are to be on the road with human users then those autonomous should be designed in a way to minimise the mistakes humans make. They should be designed that way because they can be designed that way.
- kd5bjo 9y ago
  I agree completely, and I never advocated for any change. I do, however, like to point out cognitive dissonance when I notice it on HN.
  - mantas 9y ago
    It's not cognitive dissonance at all. You're talking about safe speed based on line-of-sight. Meanwhile safe following distance is completely different matter. One of the reasons why traffic works is that we trust other drivers and rely on them.
perl4ever 9y ago
For a car traveling at 70 mph, piloted by a human, it's estimated to take about 100 feet for them to react in an emergency, and another 250 feet to stop[1] (although theoretically high performance cars can brake faster, of course). So while you can imagine everyone leaving over 20 car lengths between them and the next vehicle on the highway, it would be a radical and probably infeasible change in driving behavior. Not to mention how much slower people would have to go around curves if they didn't assume a lack of obstruction. [1] http://www.government-fleet.com/content/driver-care-know-your-stopping-distance.aspx http://www.government-fleet.com/content/driver-care-know-you...
mantas 9y ago
It is safe following distance if you can stop if the car in front of you stops. As in, you have to have time to react to the other car braking and then you have time to slow down while that car is braking. Not if a standing obstacle comes from behind that car in no time. Especially if that obstacle is not visible through the car in front of you. After all, traffic rules clearly say "no stopping on highway" specifically for that. Even shoulder is only for emergency and you have to GTFO ASAP from there.

For exactly the reason you list, what you describe is not a "safe following distance."

by kd5bjo 9y ago

For exactly the reason you list, what you describe is not a "safe following distance."

You can argue the point until blue in the face but you're not going to improve anyones safety by chasing this argument. Humans are terrible at managing risk. Humans will always make mistakes. Telling them to 'not follow closely' is futile. If you don't design systems to take account of this then your safety practices will be ineffective. If autonomous systems are to be on the road with human users then those autonomous should be designed in a way to minimise the mistakes humans make. They should be designed that way because they can be designed that way.

kd5bjo 9y ago
I agree completely, and I never advocated for any change. I do, however, like to point out cognitive dissonance when I notice it on HN.
- mantas 9y ago
  It's not cognitive dissonance at all. You're talking about safe speed based on line-of-sight. Meanwhile safe following distance is completely different matter. One of the reasons why traffic works is that we trust other drivers and rely on them.

perl4ever 9y ago

For a car traveling at 70 mph, piloted by a human, it's estimated to take about 100 feet for them to react in an emergency, and another 250 feet to stop[1] (although theoretically high performance cars can brake faster, of course). So while you can imagine everyone leaving over 20 car lengths between them and the next vehicle on the highway, it would be a radical and probably infeasible change in driving behavior. Not to mention how much slower people would have to go around curves if they didn't assume a lack of obstruction. [1] http://www.government-fleet.com/content/driver-care-know-your-stopping-distance.aspx http://www.government-fleet.com/content/driver-care-know-you...

mantas 9y ago

It is safe following distance if you can stop if the car in front of you stops. As in, you have to have time to react to the other car braking and then you have time to slow down while that car is braking. Not if a standing obstacle comes from behind that car in no time. Especially if that obstacle is not visible through the car in front of you. After all, traffic rules clearly say "no stopping on highway" specifically for that. Even shoulder is only for emergency and you have to GTFO ASAP from there.