MRandall25 wrote:The zipper is good in theory, but hard to actually pull off when real people do it.
Getting over prior to the merge point saves time in the long run, as the drivers in the open lane won't need to slow down in order to let people in from the closed lane who speed up and pass everyone, but run out of road to do so and slow down to a crawl waiting for a spot to enter.
To let the jagoff who tried to speed past everyone in, the open lane has to slow the flow of traffic, otherwise the guy from the closed lane can't get in. This causes a ripple effect to the point that a jam occurs because the original flow of traffic has to be halted to almost nothing, due in part to the people who speed in the closed lane to try to get ahead of everyone.
If everyone gets over when they see a "Lane closed, 2 miles ahead" sign, there'd be no problems. 2 miles is more than enough to find ample room and maintain flow of traffic. Problem is, people are impatient ****** and try to get ahead of everyone, and THAT is what causes the jams. Not the people getting over early.
It would actually be the exact same problem and speed as the merge point simply moves two miles down the road. You are mentally picturing a much lower traffic volume at the 2-mile sign which therefore cases no delay. However, once traffic reaches the volume of cars needing to slow down to get behind another car... the merge point all backed up but is simply 2 miles away from the closure.