• Dec 21, 2007
Finally, there's an explanation for those wasted hours we spent on the MassPike today asking no one in particular "what the (dirty word) is this (dirty word)?" A team of mathemeticians from the Universities of Exeter, Bristol and Budapest developed a mathematical model revealing that traffic jams are caused by idiots. Okay, not exactly. The real explanation is that unexpected events, such as being cut off, require slowing below a threshold speed for smooth traffic flow. As we've all observed, when the car in front of you brakes suddenly, you need to brake even harder to compensate for your reaction time; this creates a wave that radiates back through traffic. That "backward-traveling-wave" means that because of one driver's inattention, we all pay for it miles behind.
The results of the study really point up the need to drive smoothly. Roads with heavy traffic volume seem to be more prone to traffic jams, too, but that's not necessarily the case. Heavy volume can proceed smoothly if drivers anticipate and avoid sudden actions. In the end, it appears that the main way to fix traffic jams is driver diligence. The low-tech solution is to pay attention when you're behind the wheel, but we've also now got radar-based cruise control that does this for you, so you can continue blithely on your way. It boils down to common sense; be a smooth driver, expect that everyone around you is a moron, and hopefully you won't be slamming on your brakes, causing a domino reaction.

[Source: physorg.com via Motive Mag, Photo: Ed Edahl/FEMA]


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  • 42 Comments
      • 7 Years Ago
      People really are just plain awful drivers here. They pull all kinds of stupid crap where I live, from veering into the parking lane to pass you at a red light (seriously), to just being idiots who sit in the left lane doing 5 under the limit (why do people do this? WHY?!!?), to stopping at the merge to a freeway and just sitting there and waiting 5 minutes for no reason just because you have no idea how to merge when there's any semblence of traffic at all (thankfully this only happened once...but it tested my sanity dearly because all the cars in the lane she [and yes it was a female driver] was trying to merge into were exiting the freeway-and not only did those cars have their turn signals on to show that they were going to exit-they were also almost stopped because there was a buildup of traffic at the exit ramp. But apparently some drivers are totally confused about the fact that there may be traffic when you are merging onto a freeway, and insist on sitting there to try and wait until there's no traffic at all. During RUSH HOUR.

      *sigh*
        • 7 Years Ago
        290hp??? It's not enough. I want the 426ci 425HP Hemi - the REAL Hemi, not today's Hemi.

        Of course I also want to time warp back to 1968 when you could actually drive on the Northern State, or the Long Island DistressWay, instead of just idling along with one foot on the brake and one on the gas. The Thruway? Makes me sick every time. I've sick of all of it....car culture has gone to hell along with the 300 million US population and .........240,00,000 registered vehicles!!!!
        • 7 Years Ago
        It's just going to get worse when auto manufacturers are just producing fast larger vehicle price more affordable to the "general" public.

        Is 290hp really necessary for a frikin mini van ? I don't think there are any vehicles left out there rating under 130hp.

      • 7 Years Ago
      This is so old !!!
      A few years back I allready read this somewhere with a simulation using a java applet. This is the link (notice that this was written (quote)"following an article 'Und nun die Stauvorhersage' of the German Magazine Die Zeit, June 7, 1996"):
      http://www.horstmann.com/applets/RoadApplet/RoadApplet.html

      And this is a visually more apealing alternative to play with (notice that this page was (quote)"established December 3, 2001; last updated December 3, 2001"):

      http://teamster.usc.edu/~dteam/images/traffic/index.html
      • 7 Years Ago
      ... this just in, the sky is blue!

      Seriously, it reminds me of an episode of topgear where Jeremy asked why anyone would ever use brakes on the freeway, it was funny at first but then had me thinking, if you're maintaining a safe distance, and driving at the speed limit, you should have enough time to react without sending shock waves of congestion.

      Just yesterday the car behind the car behind me slammed into the car behind me simply because the driver wasn't looking ahead many many many car lengths out, it's a little entertaining that it takes a University study to add credence to common sense (the same common sense any racing school will teach, or good parent, or good friend).
        • 7 Years Ago
        I rarely use my brakes on the freeway as well. Having a stick shift helps too. Wind resistance and engine braking combine to provide enough slowing in most situations unless traffic is really slowing to a crawl or I wasn't paying enough attention.
        • 7 Years Ago
        I've always felt that brakes should be a "last resort" in controlling the speed of your vehicle. proper following distance and throttle modulation can go a long way. This is another reason I prefer manual transmission cars - you can use engine braking to slow down simply by lifting off the throttle a bit.

        There's nothing more infuriating than following someone who can't decide how fast they want to go. PICK A SPEED ALREADY! Why this is such a hard concept is lost on me. And we've all seen the resulting ripple effects.
        • 7 Years Ago
        Something to consider when touting engine braking is that there is a reason brake lights are classified as safety equipment.
        • 7 Years Ago
        Absolutely. This is definitely a "duh" thing. Traffic situations are caused by indecisive, poor drivers who often are poorly trained slushie drivers who slam the throttle to move up one inch, then slam on the brakes to stop again. Not necessary - just let a certain distance build, then just cruise with your feet off all the pedals. Never stop.

        I agree with Jeremy when he said that. That's what I've always done. To me, to use the brake is "failure" of sorts - it's sort of a game for me. Don't get me wrong, I don't take reckless chances to avoid using the brakes, but I do always plan ahead such as to drive in a way to minimize my brake usage.

        I also drive a manual, so yes, passive engine braking available in the gear you're already in helps quite a bit. At any rate, though, it's true. You really shouldn't have to use your brakes that much.

        The only times I have to are when traffic is heavy. People becomes 1000x more stupid when that happens, and you just have to hit your brakes to avoid hitting the idiots who constantly cut you off, slam on their brakes ahead of you for no reason and come to complete stop for many seconds, slow down to 30 MPH for a 40 MPH ramp, etc.

        Heh, I tell people that "I don't really drive fast, but I also don't slow down," and it is true =)
        • 7 Years Ago
        was the episode you're talking about the one where he does 800 miles in the A8 diesel? I remember him saying that to drive economically you have to really concentrate and never ever touch the brake (on the freeway). The same should go for all freeway driving in general.

        The problem is that a lot of people just don't pay attention, they don't look far enough ahead, and they use their brakes for the most useless of actions (like to slow down 1mph). Not only would traffic run smoother if people did the opposite as i just stated, but it would be safer as well.

        Also kind of goes hand in hand with how the feds are more concerned with making cars safer and letting people keep driving like idiots, than making drivers better and more alert.
        • 7 Years Ago
        This afternoon I was rudely awaken from my afternoon nap...by this GUY, HONKIN' HIS HORN IN BACK OF ME!
        • 7 Years Ago
        All you guys touting the engine braking available with manuals realize that the very same effect is present in most modern automatics, right? A lockup torque converter provides the same solid link between crankshaft and tranny input shaft. I use engine braking all the time in my automatic transmission (purchased for a multitude of reasons, next one will be a stick, I swear!) car.
      • 7 Years Ago
      I'm pretty sure they should just take away everyone's license in the northeast (I myself am from Connecticut) and make us start over. I really don't want to drive like an asshole, but I can't help it if I suddenly end up six inches off your bumper cause you randomly dropped 5-10mph. A huge part of me wishes SUV's were banned too, they're rolling roadblocks and it seems more of their drivers possess advanced retardation than not.


      Also, they need to start teaching people to get the %&# out of the left lane if they aren't passing/traveling faster than the other lanes. This apparently got lost over time, cause about 10% of drivers move over.

      I like CT and all, but 95/Merritt are just littered with idiots at all times of the day. I wish they'd make bumping legal ;)
        • 7 Years Ago
        Tele,

        I grew up and started driving in CT. I drive thru the state a lot. I hate it. The drivers are jerks, the roads suck (where the hell were the plows last sunday on 84? It's not like it was a freak storm!). It's not much better anywhere else - but GOD am I glad I left CT. If I had to sit through the stupidity that is 95S through East Lyme on a summer Sunday regularly, I would bike more.

        Wholeheartedly agree about lane discipline. NOBODY moves over. God forbid you flash to pass, either. *grr*

        Driver training in the US is dismal beyond belief.
        • 7 Years Ago
        Haha I feel that pain. NY thruway/287 westchster at 7-8pm m-f is a death sentence.
      • 7 Years Ago
      Amazing that it takes a "Team of mathemeticians from the Universities of Exeter, Bristol and Budapest" to figure this out. Any person who has driven on any multi lane highway during a busy period knows this basic fact.
      • 7 Years Ago
      And yet, people get furious with me when I maintain a 3 second following distance on the freeway in dense traffic, so that I DONT have to slow down a great deal when the person in front of me isnt driving smoothly.
      • 7 Years Ago
      traffic slowdowns are caused by vehicles driving in the wrong lanes. Not enough people drive in the right lane, and nowadays, it seems on multilane highways, 2 things happen; one is that there is so much traffic that drivers do not want to change lanes thus driving in the wrong lane; and two, there is a feeling that if one is driving in the far right lane, one is considered a slow driver. However, driving that same speed, but in a center or second from left lane, makes that person not feel like he is a slow driver, but obviously, he is, and he is holding people up.

      Large gaps in traffic (a driver who is too many car lengths behind the car in front of her) causes traffic. Get the heck out of that lane! Enforcement should be targeting those types of drivers; the ones in the wrong lane. But of course, it's easier for a cop to sit in a cruiser and just aim the radar gun!
      • 7 Years Ago
      1 thing I hate about common senseless drivers. Accidents!!! Traffic will be backed up for miles and sometimes days because of an accident. That affects both sides of the highway. I don't know how many times I have been stuck in traffic on the south bound lanes when the North side actually has the accident. Rule of thumb for the idiots that drive by an accident... Keep driving! If you cannot help the victims in the accident or if you are not one of the following
      Law Enforcement
      Nurse
      Doctor
      EMT
      Fire Fighter

      Keep it moving!! nothing can be gained by looking in awe because an accident just occured. Pay attention. That's probably why there was collision in the 1st place. Because they wasn't paying attention.
      • 7 Years Ago
      The real problem are cars following too close. Most drive so close to the car in front of them that at every little change of speed, they have to push on the brakes. It must be stress full driving that way. Also, many drivers drive in the left lane holding the flow of long lines behind them when they should be driving in the right lane. It's really a no brainer if only people had more consideration.
      • 7 Years Ago
      Auoblog readers are way better drivers than most so they're telling us things that we already know.

      What we really need are PSA's that run with info like this during all those crap TV shows that are watched by millions of morons who drive. The airwaves are public afterall. Education is the best weapon.
      • 7 Years Ago
      It's fairly simple. The attention span and focus of your average driver is awful.
      • 7 Years Ago
      I remember seeing that abandoned Bimmer in the center lane on my way to College a couple of weeks back, man what the heck was going through the guy's head?

      Thankfully, police was rapidly dispatched to the vehicle and no one was hurt.
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