Traffic jam observations

Slingshot

Expert Member
Joined
Aug 17, 2009
Messages
1,071
Reaction score
86
Location
Europe
Found an interesting article about the physics behind traffic jams, some experiments and observations:

Once upon a time, years ago, I was driving through a number of stop/go traffic waves on I-520 at rush hour in Seattle. I decided to try something. On a day when I immediately started hitting the usual "waves" of stopped traffic, I decided to drive slow. Rather than repeatedly rushing ahead with everyone else, only to come to a halt, I decided to try to drive at the average speed of the traffic. I let a huge gap open up ahead of me, and timed things so I was arriving at the next "stop-wave" just as the last red brake lights were turning off ahead of me. It certainly felt weird to have that huge empty space ahead of me, but I knew I was driving no slower than anyone else. Sometimes I hit it just right and never had to touch the brakes at all, but sometimes I was too fast or slow. There were many "waves" that evening, and this gave me many opportunities to improve my skill as I drove along.

I kept this up for maybe half an hour while approaching the city. Finally I happened to glance at my rearview mirror. There was an interesting sight.

It was dusk, the headlights were on, and I was going down a long hill to the bridges. I had a view of miles of highway behind me. In the other lane I could see maybe five of the traffic stop-waves. But in the lane behind me, for miles, TOTALLY UNIFORM DISTRIBUTION. I hadn't realized it, but by driving at the average speed, my car had been "eating" traffic waves. Everyone ahead of me was caught in the stop/go cycle, while everyone behind me was forced to go at a nice smooth 35MPH or so. My single tiny car had erased miles and miles of stop-and-go traffic. Just one single "lubricant atom" had a profound effect on the turbulent particle flow within the "tube."

It's always a good idea to drive without changing speed and without competing with other drivers for bits of headway. But I'd always assumed that the reasons were philosophical rather than practical (i.e. try to be a calm, nice person.) But my above experience shows differently. A single solitary driver, if they stop "competing" and instead adopt some unusual driving habits, can actually wipe away some of the frustrating traffic patterns on a highway. That "nice" noncompetitive driver can erase traffic waves. I suspect that the opposite is also true: normal competitive behavior CREATES the traffic waves.

Suppose we push constantly ahead, change lanes to grab a bit of headway, and always eliminate our forward space in order to prevent other drivers from "cutting us off". If tiny traffic waves appear, we will rush ahead and then brake hard, leaving larger waves behind us. Repeated action causes the waves to grow. Ironic that the angry people who drive as fast as possible might unwittingly participate in "amplifying" the very waves that they hate so much.

More here:
http://www.smartmotorist.com/traffic-and-safety-guideline/traffic-jams.html
 
Last edited:
Nice idea, but this unfortunelty wont work in JHB.
If I had to slow down like that , I'd get sworn at, hooted at etc....
 
Won't work in durbs either. As soon as you open up 1 car length, you'll find 2 taxis and a 4x4 will push in front of you.
 
Won't work in durbs either. As soon as you open up 1 car length, you'll find 2 taxis and a 4x4 will push in front of you.

That's the trick- a gap big enough to buffer your stop/starts yet small enough to discourage the boneheads from plugging it. I watch the okes on either side- any hint of a sudden manoeuvre and I speed up/slow down to close the gap and stop them. Can on occasion ruin your unbroken run, but seems worth it.
 
Over here so many car's will immediately pounce on the gap in front of you, you'd be forced to stop as there wouldn't be any 'huge empty space ahead of you'. He's also obviously never had to share the roads with our taxi drivers .. they just hang out the window in some sort-of 'I'm going in' gesture whether there actually are enough space for the maneuver or not.
 
I drive from Cape town to Worcester and there are a few rolling hills that allows one to view traffic a few kilometres ahead. The slow cars (And Lorries !!!) using the right hand lane causes major traffic jams. One you get to the top of the hill, then there are no traffic. It disappears as if the morning mist burnt them away.

Leaving gaps seems to suck cars into the front of me : (
 
Its actually the idiots who brake... If There's no need to brake, don't, it has a ripple effect in traffic.
 
I use this technique on a back road in Durbanville and it works. The cool thing is no one can push in front of you so to travel at 20km/h and build a gap, it really works and 9 times out of 10 when I reach the traffic lights they green for me and no ques to worry about.
 
Same here, I also use this technique.. I try as hard as I can to not slam my breaks in traffic.
Although it is particularity hard on SA roads when you have taxi's constantly pulling in front of you..
 
I tried this today after work, and yeah the gap doesn't stay there for long in Durban traffic! What it did do is calm me down a bit and made my ride smoother with less braking. If someone shoves into the gap, I just make a new gap. That driver just left a gap in the lane next to you, so in some way it does help a bit. I drove more considerately than usual, giving people a gap instead of trying to stop them cutting in. Overall my drive home was much more relaxing.
I also experienced bottlenecks where drivers try to see why a copcar is parked on the other side of the freeway. All the traffic on this side slows down to a crawl as drivers try and see what's happening. Stupid, but so typical human nature.
 
Nice technique indeed, but unfortunately (as many have said) South Africans are simply too aggressive on the roads and will take up that space in front of you, even if just for the sake of being in front of you as oppose to (and heaven forbid) begin behind you. On single lane roads it works well, especially if there is little chance for overtaking.

If only everyone was forced to take a chill pill before leaving for work / home, this might stand a chance :)
 
Top
Sign up to the MyBroadband newsletter
X