I always wonder why so many people observe this when I never have. It makes no sense logically; it's the speed of the car in front of you that determines whether they should switch lanes, not the size of the gap behind it. There is no reason for them to cut in when your lane is no faster. Perhaps you are just the sole person leaving enough room for people to execute needed lane changes.
At any rate, even if people are continuously going around you like water going around a rock in a stream, you only have to drive 2 mph slower than traffic to constantly rebuild your following distance from the infinite stream of cutoffs. But my experience is the majority of following distance is eaten up by people randomly slowing down, not cutting in.
In the auto cruise example, it’s leaving perhaps 2 - 2.5 car distances. In close traffic the average human I would bet is leaving 1 or less then 1.
The issue is not that I can’t rebuild the following distance, the point I’m trying to make is that even if I constantly rebuild the following distance it sets off a cascading effect.
I’m following at set speed, car cuts in front, hits brakes, I now slow down, car behind me slows down, I rebuild following distance and car perhaps 7-8-9 cars behind me repeats because at some point the cascade magnifies to a larger slowdown behind.
Can I mitigate this by manually letting my distance be closer for a time, and slowly easing to larger ? Yes.
But if I allow the car to do it automatically, it will increase the follow distance at a rate that causes a cascade in tight traffic.
Though - I do think with these discussions on HN- it does depend on where you’re driving.
My experiences are centered on East Coast, thinking of route 80, 81, 83, etc. or Philly / New York City.
The driving experience is radically different in California, Florida , or the mid west.
I would say when driving in California people seem to navigate traffic better. (SF, LA) then on drivers on 80/81/83.
(Or perhaps it’s due to better designed roads ).
> In the auto cruise example, it’s leaving perhaps 2 - 2.5 car distances. In close traffic the average human I would bet is leaving 1 or less then 1.
At 60 kph (16.7 m/s) 1 car distance (about 5 m) is less than one third of a second. Even 2.5 car lengths is less than a second. I use traffic aware cruise control on my Tesla set to the maximum separation which is about three seconds, so 50 m at 60 kph.
Three seconds separation is in fact the recommended following separation in most European countries and in Germany in particular 0.9 seconds or less can result in a hefty fine, see https://en.wikipedia.org/wiki/Two-second_rule
In the UK some stretches of motorway have chevrons marked on the road indicating the required spacing at the speed limit.
At any rate, even if people are continuously going around you like water going around a rock in a stream, you only have to drive 2 mph slower than traffic to constantly rebuild your following distance from the infinite stream of cutoffs. But my experience is the majority of following distance is eaten up by people randomly slowing down, not cutting in.