• LurkingLuddite@piefed.social
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    16 hours ago

    Nothing about the zipper merge says, “last minute”. It is wholly and entirely about matching speeds and making room.

    Guess what dictates the speed of the lane that gets to travel forward? The amount of traffic that gets to travel… in that reduced number of lanes.

    The people racing to the end of the closing lane are doing nothing but increasing traffic density, which directly hurts the effort of zipper merging. If it’s going from two lanes to one, the density MUST halve somewhere if traffic is full. That’s never going to happen at full speed if there are assholes wedging in at the last second and pushing traffic density past what people comfortably go full speed at.

    Hint: it is not bumper to bumper on the highway.

    Again: Merging at the last second does nothing but push traffic density up. Often past comfortable densities, which will slow traffic. It’s the exact same reason rolling stops happen even without traffic accidents or lane closures in dense traffic.

    • Randelung@lemmy.world
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      15 hours ago

      Last minute is absolutely part of it. Use the available queueing space to keep congestion from spreading. I don’t know where you drive where bumper to bumper didn’t happen, though.

      • LurkingLuddite@piefed.social
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        13 hours ago

        No it is not. Ever. You cannot magically add throughput by cramming in ahead of the bottleneck. That ONLY increases density, which DEMONSTRABLY reduces speeds.

        Guess what happens when speed goes down? Throughput also goes down! You cannot magically add throughput by filling space beyond what is reasonable for the speeds you want to go. That’s not how humans work.

        • Randelung@lemmy.world
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          11 hours ago

          It’s not about throughout. You want previous intersections and ramps to be free. The extra lane is car storage space. If one lane is stopped and the other is free you absolutely move up to the merge point. Safely, mind you. The speed limit is way too fast, 30-40 kph is enough. Merging early causes shockwaves that turn into full blown stops upstream. Plus you block the whole lane until you’ve merged.
          I’ve done traffic control systems for almost a decade so I actually know a little about the subject.

          • LurkingLuddite@piefed.social
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            9 hours ago

            In some situations, it’s not all about throughput.

            Though traffic congestion is ALWAYS about throughput. You want less congestion? Then don’t rush to the end of a closed lane and cram in. That ALWAYS hurts throughput, which ALWAYS increases congestion. Period.

            Sure, if traffic IS backed up to other roads, then absolutely, fill up the closing lane and get off those other roads, though understand that filling up that lane will, always, always hurt congestion if throughput is already struggling.