Two car lengths on the highway is not enough car lengths to make a meaningful difference in the event of a crash or giving you time to react to an emergency situation up ahead.
That being said, I respect that you leave any car lengths at all and it's probably better than nothing. Especially since other drivers see any more than that as a challenge to enter that gap. Which is dangerous as shit and they are wrong but won't learn even after they wreck doing it.
I think the safety guidelines are 3 seconds of reaction time which comes out to about 1 car length per 10 MPH of speed.
But yeah, good luck with that because other drivers just see that as space they can merge.
Sometimes all traffic is speeding along, as in 5-10mph over the speed limit, and it looks like pack racing. I keep thinking, all it takes is one distracted driver and it's a 30 car pile up.
Let them merge. I'd rather give space for those who drive aggressively than be hit. It won't really affect the time it takes to get from A to B, it reduces stress and accident probability, and I don't lose points for some race we're not in. I know some people get mad at passive drivers, but if I'm going around the speed limit in the right lane minding my business, why are you so mad I'm not participating in increasing insurance profits?
This was my first thought. When I learned how to drive, the rule was one car length per 10 mph. So at highway speeds of 70, that would be 7 car lengths of space to ensure enough distance to safely stop or avoid a collision. I see approximately 0% of people following this rule nowadays, and while I try to maintain it myself, it often results in a stream of vehicles merging in front of me and messing up my distance. Fun times.
Handy tip:
In the USA, the lines on a highway are 10 ft long, the spaces between them are 30 ft.
So, a line and a space are about two car lengths. It’s a handy way to judge how close you are to the car ahead. At highway speeds, you want 3-4 lines between you.
This is the way
Me: (Leaves the appropriate number of car-lengths for the present speed between me and the vehicle in front of me)
Some jerk who should have their license revoked: [No turn signal] I merge here now!
Confirmed: humans are cats
While they should of course be signaling, that space is for merging. Let off the pedal for one second and you've likely got your gap back anyway, not a meaningful disruption.
You need to leave at least 3 seconds of reaction time between you and the next car, 2 car lengths at that speed is too close for you to reliably react in time.
Also, people can't reliably judge a "car's length". It's a ridiculous measurement system, let alone travelling at 100 kmh.
Timed gap makes so much more sense and it remains mostly consistent regardless of speed. As in, you should have 3 seconds of gap regardless of if you're traveling 20 kmh or 100 kmh.
Are they talking average car length, your own cars length? One of my cars is a little over twice as long as one of the others. Timed gap truly is the better rule.
You forgot about a gamer's reflexes. 2 car lengths at 200 km/h are fine. Give or take the condition of your brakes and tires.
Any% no-brake 200kmph 2 car length speedrun
I once had to be in extreme traffic during a commute behind an asshole who tapped the breaks every ten seconds or so. In retrospect, I should have changed lanes or exited and re-entered the highway. I was behind that asshole for like 45m and I was screaming with rage.
I sold my car and gave up driving after I quit that job. Didn't drive for 10y. Won't ever accept a job with a commute again.
This is not a problem if you drive at the speed limit. Then what happens is that everyone else, who will be speeding, will continually pass you and thus create more car lengths in front of you. Unless you're in a no passing zone on a two lane road, in which case they can follow the speed limit for once.
Even then, at the absolute first available opportunity:
It's the 2+ car lengths when at a traffic light that baffles me.
The entire time you spend sitting at a light after it turns green is solely to wait for those gaps to reappear.
The correct stopping distance, as I was told, is "far enough back to see where their back tires touch the ground". Pretty good rule of thumb. Gives more space for larger vehicles who may not see a jaywalker in front of them.
Nothing to gain by being right up the ass of the car in front of you. Unless maybe you realize you're blocking the entrance to a business/secondary street and you try to be "nice".
I dunno I find the drivers who dart around me in the slow lane really like having that space to dart back into.
Try that on the NJ Turnpike and see how fast two cars jump in that space.
My driving instructor said leaving 4 seconds of distance was safe for highway speeds. Ok busy highways the best I can get is a few car lengths.
I love setting my auto cruise control and watching everyone flood in front of me to just go the same speed they were going behind me.
Remember the follow rule. If the vehicle in front of you is a car, stay 3 seconds behind. A tractor trailer, 4-5 seconds. An emergency vehicle, 6 seconds.
And if the car next to you is a tandem semi, be sure to cut them off while going downhill right before the traffic jam.
Fucking idiot's, all of them.
Halbe Tacho (in mm)
In this same vein, I loved social distancing while standing in a line. Why do we have to cram in uncomfortably? It won't make the line move faster.
Half a meter is fine when I'm in need of bullying away the car blocking the fast lane on the Autobahn. Sometimes they act like they had not rear view mirrors and the road was their own.
