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xkcd #2932: Driving PSA
(imgs.xkcd.com)
Alt text:
This PSA brought to you by several would-be assassins who tried to wave me in front of speeding cars in the last month and who will have to try harder next time.
I have a question on this. Let's assume everyone is a perfect driver and must have at least a 2 second following distance at all times. If there's a free flowing queue of traffic on the highway with 2-4 second gaps between, merging in is impossible without someone slowing down and letting you in. Every time I merge this situation stresses me out.
Merge into the gap, then slow down slightly to extend the space in front of you, and let the guy behind you slow down to extend the space in front of him. It’s not complicated
At 100 km/h (low-end highway spreed), or 1,666 m/minute, or 27.7 m per second, a 2 second gap leaves approximately 56.6 m (185.6 feet) between cars. With the average car length being ~4.9 m (~16 feet), even the absolute worst driver can merge in a space ten times the size of the average car, assuming they're matching highway speed.
Most people have no actual concept of how long 2 seconds actually is or how much space it would leave in reality.
Yeah, obviously you "can" merge, but in doing so you insert yourself into the middle of a 2 second gap creating 2 × less than 1 second gaps. Like I said, in this hypothetical everyone is a perfect driver that always follows the rules, so that's not an option.
For that matter, the driver behind should see that you are about to merge into a gap that's too small and slow down to leave a space that's at least 4 seconds big.
I'd also like to point out that your attitude to driving is terrible, the size in meters of anything on a highway is irrelevant, 2 seconds is not a lot of time to react and slow down a car at 100, and that just because you "can" do something doesn't mean you should.