Merging Lanes

You’re probably shifting out of your lane too soon.

Driving back from Yosemite on Thursday, Caltrans had shut down the right three (out of four) lanes on I-5 in Castaic. We lost one lane at a time, and the first merge was the slowest. Each next one sped things up, until we were all in a single lane, and moving at a reasonable speed. Part of the problem was that much of the traffic in the right lane was trucks (we were already in the left lane when the backup started). It added about twenty minutes to the trip time.

11 thoughts on “Merging Lanes”

  1. I wonder where they got the “up to 40% faster” statistic. The video has cooperating drivers in the moving lane and aggressive drivers in the merging lane; if you get two or three non-cooperating drivers on your left or one non-aggressive driver ahead of you, you now have to merge from a dead stop. Merging early is asshole insurance (yeah, I’m an early merger).

    If the open lane is at max capacity past the obstruction, merging policy doesn’t seem like it would do a thing to affect how many cars go past the bottleneck per unit time, unless you’re considering secondary effects from disruptions in the flow due to merging (and introducing those disruptions at max congestion doesn’t seem like a good idea).

    I see the video is from Canada–maybe they have nicer, better behaved drivers there.

      1. “Assume wrongly” is the key. Obviously the author has never driven or ridden in a car on the Interstate. Just put a sniper in the lane that’s closing. Open fire on queue jumpers. Problem solved. Open up a parking lot: “Free cars! Small hole in windshield on driver’s side. Blood on some upholstery.”

      2. There’s kind of an analogy to on-ramps that dump directly (or though a small acceleration lane) onto a high traffic road. In that case, it’s friendlier if the cars alternate (that decision gets messy, too–if the traffic on the road is light, it’s better if oncoming traffic doesn’t yield an inch and lets the merging car find its own room; if the traffic is heavy it’s nicer to do the zipper trick).

  2. Truckers with CB will co-ordinate in all lanes and will allow their rigs to run in parallel. Allowing all traffic in front of them to merge ahead but nothing can go around them. Then once the traffic has cleared in front they proceed in formation at a constant 35 mph or whatever is prudent until the merge point at which point the non-ending lane driver slows down to allow the ending lane driver to merge in front and then continue at whatever speed. No stop and go. Much less shifting and breaking. Easier on the rig and easier on the fuel. But you need that back channel comms to make it work. Gotta admire the pros.

  3. If everyone merged at the soonest safe opportunity, you wouldn’t have the bottleneck created by inconsiderate assholes trying to merge at the last moment, forcing everyone else to slow down.

  4. Also, the video cheats. The zipper merge video has much less traffic than the moderate-to-heavy example, and they seem to be cheating on the before merge/after merge spacing and speed. It almost seems like the post-merge traffic is moving faster than the pre-merge traffic (it’d be nice if the “simulation” showed a bit more of the merged traffic).

    Of course, that is one way to do it. Drive 30 mph when you have two lanes, 60 mph when they neck down to one. It’s a bit of a challenge to drive at twice the speed while maintaining the same separation and also rubbernecking to see what caused the slowdown, but, hey, Canada.

  5. Yeah, I’m one of those a-holes who will, upon getting close to a zipper, stay in the left lane but pace the vehicle in the right lane. This allows those ahead of me to merge in without other obnoxious phoques zooming in to merge at the last minute and make everyone wait. I will usually see someone do the same thing about a couple hundred yards or so behind me, sometimes a truck, but not always.
    The benefit is that the people ahead of me can zipper in properly, folks don’t have to ride on each other’s bumpers to stop those obnoxious phoques who want to jump to the head of the line from squeezing themselves in, and by the time I get to the merge traffic is starting to move at a reasonable pace and is no longer stop and go.
    Don’t like it and think I’m an arse? Too bad. Someone has to stand up for the chumps who abide by common courtesy, as I’ve been that chump who merges when notified and then sits in traffic as car after car after car goes zooming by in the left lane far too many times.

  6. When I’m in that situation, I can’t help reverting to my Top Gun days. I feel the urge…the urge…TO MERGE!

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