I mean, you have one or to stragglers, but for the most part, there are usually ten to twenty cars all traveling together going down the road, in groups or herds (as I like to say) at any given time.
Have there ever been studies on this phenomenon? Why does traffic travel in groups? I personally think that there is safety in numbers and most people are followers, not leaders.
*I was going to put this in General Questions, but I don’t know if there is a factual answer, so if there is, would a MODERATOR move it? *
IME, herds are caused by a car in the right lane driving at say 65mph and a car in the left lane driving 65.001 mph. The car in the left lane is sloooooowly passing the car in the right. Meanwhile there’s 18 cars that want to travel at 70-75 mph and are just waiting for the 65.001 mph car to get out of the way.
When at all possible, I just set my cruise control at the speed I want. I pass the cars that are slower than me and stay in the right lane so the ones that I am slower than can go around. I try to avoid the herds.
ETA: this is, of course, for interstate driving. For city driving see the post above mine.
Because there are a LOT of people who somehow cannot manage to drive on their own initiative. They affix themselves to the bumper, side or near another car and rely on that driver to maintain a proper pace, as opposed to paying attention and doing it themselves.
That’s why you have Klingons. You know the type. There are two cars on the road ahead of you in the right lane, one tailgating the other. You pass by at about 5mph faster than they are going. The one who is tailgating the other suddenly passes the one in front and begins tailgating you. This person will continue to do this until a more suitable target impresses itself upon their mind.
Yesterday going to work, I had a similar incident. Lone car in the left lane. It’s victim had just merged right and exited the freeway. I pass in the center lane, doing the speed limit. Car begins to pace me, right in my blind spot where I cannot see it. Three miles later it is still right there in that same relative position. I suddenly slow down (because I’m coming up behind people) and turn to look the moron in the eyes as she pulls up next to me. Person looks confused, passes me and begins to pace the car in front of me in the same position, nearly 10mph slower than we’d just been going.
Yeah thanks. I’d really have liked to continue going the speed limit. Sorry you’re too stupid to drive on your own.
Probably because it’s a lot easier to follow someone that is going what you feel is an appropriate speed than to consistently monitor your own speed while driving.
Often on a wide open freeway with no other cars around if there is no one to pace yourself with it’s too easy to get going too fast if your not paying attention.
It’s a lot easier to find someone going 70, decide 70 is a good pace, and just follow along without having to think about it.
Metering lights are designed to provide a steady flow of merging traffic, and in my experience ramps without metering lights cause more bunching than ramps with.
But I have a better example. I used to cross the Bay on a bridge where all traffic going Westbound went through the toll plaza, and was thus metered. The bunching started within half a mile, and it seemed to be caused by slowpokes on the left, as many have said. If I could sneak through the logjam, my speed increased from 40 to 60. I’ve seen this on freeways also, but the bridge was a more controlled situation, with no entrances or exits for quite a long distance.
Even if nobody is pacing off anyone, clumps will still naturally form.
Imagine a uniformly distributed crowd of light traffic on a highway with, say, 3 lanes going one way. Everybody is going exactly 65.000000 mph.
Now re-engage the real world & let them start to randomly vary their speed, even by 1/2 mph. The fast ones will catch up to the ones ahead, while the slow ones will fall back until they get caught up to by folks behind.
Pretty soon you’ll have a bunch of gaps & clumps with slow-pokes in the front of each clump and would-be speedsters in the rear of each clump.
Individual speedsters will eventually push through their clump, only to zoom through the empty space & join the back of the next clump.
Lather, rinse, repeat.
In traffic engineering parlance, the clumps are called “platoons.”
Driving on the interstate in the wilds of Wyoming recently, I had the sheer, sweet pleasure of encountering nothing but courteous drivers. I set my speed at 5 above the limit and just cruised, passing lovely folks who set their speed right at the limit and stayed right. Af a safe distance, I’d move to the right lane, and would be passed few minutes later by someone set at ten over.
Coming back to the bay area in moderate traffic (at 11:00 pm!) was like some spasmodic parody: a line of cars going just under the limit in the left lane and just a few stragglers in the right three lanes. That’s right. A four lane highway, with signs fer chrissake saying “slower traffic keep right,” and bay area drivers somehow manage to simulate a traffic jam.
In eleven years here, I’ve never figured out why the left lane is the slow lane. Or why there are areas in which the left lane stops while the middle lane moves every single day. What kind of idiots stay in the left lane day after day? Are they thinking, “duh, left lane fast me stay here, maybe today it will move?”
There seems to be a wider variety of idiot drivers here than in any other place I’ve driven - and I’ve lived near Boston.
The one thing I miss about Texas is the unbelievably courteous drivers. If you’re driving, and you come upon someone who is driving too slowly (say on a two lane, or even a 4 lane depending upon its location), they’ll actually slow and pull over to the shoulder to let you by.
Then, the courtesy is that you give them a little blinky blinky right turn signal blinky blinky left as a visual thank you.
Too damned nice and cute! Sorry, it doesn’t answer your question about clumps though.
Not “metering lights” that regulate the traffic on the ramp (and which I’ve only seen in large cities (LA, Chicago, and NYC are three cities that I remember having them)), but regular stop lights placed at the intersection of the on-ramp and the… feeder road (?). The light turns green and 20 cars fed onto the highway in a couple of minutes time. The light turns red and the flow of cars onto the highway stops for 2 minutes. Repeat every 4 minutes.
There is also the self-righteous brigade. They feel entitled to do the speed limit no matter what lane they’re in whether or not they impede traffic. After all they’re right.* Combine a few of those with a few sheeple and you get herds.
*I have no idea if the poster in the link may have changed his views over the course of the thread, I merely used that post as an example of a type of thinking.
This website has basically made me pledge to myself to change my driving habits.
My whole life I’ve had cars that could barely go 75. I just bought a new one, and now that I can actually control my speed in that range it’s amazing the different behaviours I’ve observed. In the past, I’ve just hammered on the gas, and hoped for the best. Now, I no longer feel I have to “win” by passing people, because I know my engine can totally blow them away, anyway. Now if Santa Fe would just start timing their darn lights, I wouldn’t be as agitated in the city, either.
And, of course, there are those people who are sticking with the pack in order to avoid speeding tickets. I’ve always been told that if you’re going to speed more that 10 miles per hour over on a highway, make sure that you’re not the first in line or the last, as those are the ones who will get pulled over.
