The Phantom Traffic Jam

[Ben]

Explaining the "phantom traffic jam" that you sometimes hit, which seems to clear up with no rhyme or reason and no sign of an accident or roadwork. I always suspected it was something of an Occam's Razor answer, especially all the times that I yelled out, "It's got to be one stupid idiot!" 

The theory that these migrate was somewhat interesting.

http://www.clickexist.com/2013/03/09/the-phantom-traffic-jam/

[Boomhauer]

Joccassee, Lupinus, Revdisk, and I ran into a hell of one of these coming up I-95 on Sunday after Thanksgiving last year. Frickin idiots who don't know how to drive...

[mtnbkr]

Those things are common as hell in NoVA.  I seem to hit one on I66 weekly.

Chris

[SADShooter]

I do a lot of driving on I-35 in Texas when visiting family, often around holidays, and this is a regular occurrence on rural stretches of highway. One notion in which I'm fairly confident is that more drivers with little highway driving experience are on the roads at these times, and they are prone to overreact/over-correct, or simply don't have the confidence to drive at highway speeds. So, unusually high volume plus more idiots hesitant drivers equal phantom traffic jam.

[zxcvbob]

It's just a standing compression wave.  It will last as long as enough cars are entering the back to sustain it.

It might even have just been caused by an engineer who had a bad day, realized the road was operating at near capacity, and hit the brakes briefly to share the joy.   

[AZRedhawk44]

Waves propagate through one another.  Sound, light, water, whatever.  In this case, stupidity.

The reverse delta change caused by driver perception, reaction, and braking has higher negative velocity than the positive delta change from vehicle acceleration.  As such, the phantom traffic jam runs "backwards" down the highway.

[French G.]

It's just a standing compression wave.  It will last as long as enough cars are entering the back to sustain it.

It might even have just been caused by an engineer who had a bad day, realized the road was operating at near capacity, and hit the brakes briefly to share the joy.   

Pretty much, but the output of the wave is less than the input due to stacking reaction times. So, it gets worse. One touch of the brakes up front is a panic stop 30 cars back. I am pre-programmed, I am going for clear space before I brake, no matter where that is. Most folks are quite content to lock them down and rear-end each other. I despise people that start these, probably from being in a race car. Very common for a leader to run up the speed pre green flag, then slow everyone up before going. Wreck waiting to happen. From the flagstand or fan perspective you get a crappy strung out start. In my case though, flag man is an a-hole, I'll let them try again.


Even at constant speed I will pick through a 2 mile clot of bumper to bumper morons to discover clear highway in front of one idiot who wants to pass a truck but can't read the instructions on the gas pedal. 2 miles of tailgating people just trying to wreck from one idiot. Slower traffic keep right! If I end up having to pass said idiot on the right I don't cut them much slack. Or room.

Oh, and you merge with your gas pedal, not your brake. No excuse to not be at the prevailing speed and match a hole.

[AJ Dual]

I'm trying to find it, there is some engineer who had a theory that a few "seed cars" driving in and through the compression wave style traffic jam could clear them up.

The main thing they needed to do is simply coast as much as possible so they didn't catch up to the cars in front of them, or worse, hit them, but do so without lighting up their rear brake lights causing the cars behind them to not hit their brakes, and the lights and so on...

And in doing so they could decompress the wave.

[French G.]

Well, usually if you can clear the idiots causing the trap others who are tired of being trapped speed up and clear them too.  The problem is the close proximity and the speed changes make everyone in it angry, scared, or both. Then they drive even worse, especially since the default solution seems to be to tailgate because obviously it is you who is the problem, not the 50 cars in front of that you are following. Then gets introduced the pass on the right, usually followed by slamming on the brakes to fit in the hole, also making things worse. I pass on the right, but only if there is a clear benefit and I can get somewhere substantial, not just jackwagon myself into someone else's following distance. I take my following distance personally, that's my road.  I love to watch people try to use it.

[Ben]

I'm trying to find it, there is some engineer who had a theory that a few "seed cars" driving in and through the compression wave style traffic jam could clear them up.

The main thing they needed to do is simply coast as much as possible so they didn't catch up to the cars in front of them, or worse, hit them, but do so without lighting up their rear brake lights causing the cars behind them to not hit their brakes, and the lights and so on...

And in doing so they could decompress the wave.

I actually try to do this when I hit the ones that often occur on my way to work. Usually I see two things happen: Jerks behind me don't see my brake lights go on and get right on my tail instead of keeping a safe following distance that allows them to keep moving as well, and/or because I'm leaving space between me and the person in front of me so that I can coast, some other jerk(s) squeezes in and then hits their brakes, forcing me to brake.

I'm guessing if people could get out of the tailgating habit, a lot of these would go away. Also the people who are mad about being behind someone going 57MPH, so instead of punching it and going around and back into their lane, they get in the fast lane and pass the "slowpoke" at 60MPH.

[Mannlicher]

that's a Brit video. Their problem is that they drive on the wrong side of the road. 

[Tallpine]

that's a Brit video. Their problem is that they drive on the wrong side of the road. 

In Gaelic, the word for "left" is actually the same as the word for "wrong"  (cearr)

 

[Cliffh]

Pretty much, but the output of the wave is less than the input due to stacking reaction times. So, it gets worse. One touch of the brakes up front is a panic stop 30 cars back. I am pre-programmed, I am going for clear space before I brake, no matter where that is. Most folks are quite content to lock them down and rear-end each other. I despise people that start these, probably from being in a race car. Very common for a leader to run up the speed pre green flag, then slow everyone up before going.* Wreck waiting to happen. From the flagstand or fan perspective you get a crappy strung out start. In my case though, flag man is an a-hole, I'll let them try again.


Even at constant speed I will pick through a 2 mile clot of bumper to bumper morons to discover clear highway in front of one idiot who wants to pass a truck but can't read the instructions on the gas pedal. 2 miles of tailgating people just trying to wreck from one idiot. Slower traffic keep right! If I end up having to pass said idiot on the right I don't cut them much slack. Or room.

Oh, and you merge with your gas pedal, not your brake. No excuse to not be at the prevailing speed and match a hole.

*Commonly referred to where I come from as "brake checking".  Good way to get a talking to in the pits after the race is over.  BTDT, the talking to that is.

As for getting up to speed when entering - that's a pet peeve of mine, if you're getting on a road that has a 75 mph limit on it, at least get to 65 while you're still on the on-ramp!  I've actually seen idiots hitting the brakes on the on-ramp with no-one in front of them.

I'd really like to get my hands on the damn fool idiots that designed the on-ramps around the DFW/Tyler area (in TX).  To get on the freeway one must first drive along the parallel service road, cross over an on-coming lane of traffic, get onto an extremely short elongated S shaped on-ramp and accelerate to highway speeds, sometimes in less than 100 yards.  I don't mind it too much when I'm by myself, but SWMBO doesn't care much for getting tossed around the cabin.

[vaskidmark]

that's a Brit video. Their problem is that they drive on the wrong side of the road. 

They are still driving their wagons to market, or riding their chargers in hopes of jousting with another knight.  There's never been a good explanation of why the driver's position in the USA shifted from right to left.  And of course at one time in the early history of automobiles the driver was in the center so he could get a full swing to either side with the tiller.

stay safe.

[birdman]

They are still driving their wagons to market, or riding their chargers in hopes of jousting with another knight.  There's never been a good explanation of why the driver's position in the USA shifted from right to left.  And of course at one time in the early history of automobiles the driver was in the center so he could get a full swing to either side with the tiller.

stay safe.

The logic for LHD (US) is based on the center controls of early cars--since most people are right handed, it made sense to make the "standard" position the one where the driver's dominant hand is on the tiller.  Since the first cars, and the first mass produced cars were in Germany (LHD) and the US, it makes sense that they did it this way, and the Brits changed it to their way,

Same reason why the pilot sits on the right in a helo, the cyclic is more important than the collective, so it gets the right hand, and the collective gets the left.

Though, one could then say, now that the controls in a car are centered on the driver, the RHD Brit way actually makes more sense---the dominant hand gets the wheel, the other hand the gear shift.
And us lefties get an advantage in LHD cars in racing :)

[Fly320s]

Same reason why the pilot sits on the right in a helo, the cyclic is more important than the collective, so it gets the right hand, and the collective gets the left.

Does that mean the Hughs/MD 500 is British? 

[birdman]

Does that mean the Hughs/MD 500 is British? 

No, it means the md500/h-6 is weird...and annoying to adjust center controls

[grampster]

We have a 1700 mile trek from W. Michigan to Key West.  This year we experienced basically bumper to bumper traffic the whole way.  Over 3 days we had at least 3 or 4 of these clots each day.

We planned to leave to head south on Dec. 26th, but a blizzard went through the Ohio valley and hit Indianapolis particularly.  Our route takes us through Indy.  So we delayed the trip till the 27th to allow for snow plowing etc.  So what I think happened to create this 1700 mile traffic jam is this:  One group of snowbirds were leaving the 26th, but delayed one day due to the storm.  Another group was heading south on the 27th, so two days worth of snowbirds wound up on the route south on the same day, thus doubling the volume which exacerbated the potentiality for the clots. 

We hit one slowdown near Ocala that lasted for several hours.  We crawled along for a couple of miles at perhaps a couple mph.  We exited I-75 by a Holiday Inn, checked in, went to dinner and could see I-75 out the window.  It was still crawling 2 hours after we got out of that mess.  The following morning, there was nothing anywhere to indicate why the jam of the day before.  No construction or no accident debris was evident.

[CNYCacher]

One of my favorite youtubers.  I've been doing this for years as well.

http://www.youtube.com/watch?v=iGFqfTCL2fs

[Fly320s]

No, it means the md500/h-6 is weird...and annoying to adjust center controls

Yeah, but I still want one. Thanks to Magnum, PI and US Army Special Forces.