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How long is seven car lengths in seconds? In open traffic, I prefer to just maintain constant speed and move left one lane whenever someone is slow in front. T
by Noumenon72 8y ago
How long is seven car lengths in seconds?
In open traffic, I prefer to just maintain constant speed and move left one lane whenever someone is slow in front. That would be a cool setting for a cruise control.
- foxthatruns 8y agoTotally depends on the speed. If we're both going 40 mph and a car is 15 feet long, then 7 car lengths takes me 1.8 seconds. But if we're going 80 mph, it's only 0.9 seconds.
- CalChris 8y agoThe setting is 7 car lengths and I think that's for 60 mph or so. It is proportionally less at lower speeds. Google tells me that 7 * 200 inches / 60 mph is 1.32 seconds which isn't that long. But in reality, the car in front of you is braking and you are braking. So the real measurement is when they hit the brakes can you react in time to hit the brakes. Not gonna do that math. Maybe the CA drivers handbook has a table. However, 7 car lengths feels to me like a lot and 7 car lengths with TACC seems very safe. Yeah, people merge into my gap and so I drop back again; big whoop. It also reduces dings from pebbles getting kicked up by the car in front.
- jdietrich 8y agoThe NHTSA treat 1.5 seconds as a typical reaction time, so seven car lengths is really rather marginal at 60mph. https://www.nhtsa.gov/nhtsa/Safety1nNum3ers/august2015/S1N_Speeding-August2015_812008.pdf https://www.nhtsa.gov/nhtsa/Safety1nNum3ers/august2015/S1N_S...
- mcguire 8y agoThe general advice I've heard from various safe-driving classes and state driving booklets is 2 seconds at any speed.
- CalChris 8y agoThis begs the question as to why Tesla doesn't have a setting for 8 car lengths. I thought it might be car length but the car length average seems to be 204 inches which is 1.35 seconds. In any case, this 7 car lengths is for TACC rather than human decision.