Traffic congestion mystery?

Question

I don't understand if 1 car can go 60 mph on a freeway with relative ease, why can't 1000 cars going in the same direction ALSO go 60 mph with relative ease? Why is it that as the number of vehicles grows, the slower everyone seems to go? On a road with no control devices such as stop signs & traffic lights, shouldn't it be theoretically possible for a group of vehicles to travel at the same velocity as one? Sort of like a stock car race: a few dozen cars traveling rapidly & bunched fairly close together (so speed, in and of itself, is not the obstacle). Is the problem the entrance/exit to & from the freeway? Is it simply the random mix of idiocy, people changing lanes, larger vehicles vs smaller ones?

Is it unavoidable human nature to gawk at a car wreck, thereby slowing down people behind you?

Every day I hear traffic reports of accidents at the same locations & I wonder WHY??? And, with that knowledge, can anything be done to decrease the probability of repeat accidents?

Answer 1

Becouse the female drivers get scared! no realy people get more aware and coutious, they slow down and it couses everydody else to slow down. Its a chain reaction

Answer 2

You seek relativity a logical relationship between time and space. There is no logical relationship between time and space in a traffic jam. All it takes is a couple of minutes for the traffic to stop. Someone breaks down, or an accident, maybe a deer or a squirrel. Deers and squirrels should not drive...what else can i say?

Answer 3

You are forgetting how much space those vehicles take up.

Let's say you have a 3 lane highway with those 1000 vehicles. At 60 MPH, the length of the vehicle plus a reasonable space between for safety - let's say a combined 350 feet for both. Each lane would have 333 vehicles, so 333X350 = 116550 feet, which is over 22 miles!

Even if you say 350 is too much, or maybe the highway has 4 or 5 lanes instead of 3 - you get the point.

Make more sense now?

Answer 4

Think of it like this:  if one gallon of water can go through a pipe per minute with relative ease, can you then cram two gallons per minute through the pipe?  What will happen?

Same thing here.  Engineers actually use the same equations when modelling traffic flow.  The more cars there are, the more space they need, since each car has to keep a certain distance from the next car.

Answer 5

people are dumb asses and they to scared they will get pulled over

Answer 6

We could all cut our drivers licenses in half and walk to work.

Answer 7

Let's start with the speed limit.  It's just that, a limit you may not legally exceed, not to say we don't when we can, but that's the way the law is written.

So, say the car in front of you, isn't doing the speed limit.  You can't go any faster than the car in front of you, so you change lanes to pass.  The car which was doing the speed limit, that you just pulled in front of, has to slow down and wait for you to accelerate to the speed limit. The car behind him, ducks to the left when he sees brake lights, causing the person in that lane to slow down to avoid a collision.

And in stock car races, some cars are faster than others, some drivers are better than others.  It's just better managed because per mile, there aren't as many cars on the track as there are on the interstate.

Many times, people merging onto a freeway are afraid of getting run over, so they slow down to get a better look for a better hole they can get into.  People that stop on the entrance ramp, in my opinion, should be cited.  I watched, once, as a car stopped in a cloverleaf and caused a backup that literally lasted for 3 days.

Some vehicles have to slow down before exiting a freeway, and I know of at least one city that's raking in revenue by clocking vehicles coming down the exit ramp.  And since many driver's don't comprehend "yield to ramp" signs, getting your speed down prior to dropping down a short ramp is a matter of self defense against some dimwit on his cell phone who can't comprehend that his rush to the office is not more important than someone else's safety.

Larger, heavier vehicles take longer to accelerate to speed and slow from speed to a stop.  Towing a trailer of any size hampers the operations of accelerating and slowing, as well as changing lanes to get around some idiot who was slowing down on the entrance ramp to get a better look at traffic.

Contributing to the problem is the growing number of drivers that don't grasp the concept of "drive right."  Meaning that if people start queeing to pass you, and there's another lane to your right, you need to move over.

Rubber-necking is a problem at times, hence laws that require operable vehicles be driven out of traffic after a wreck and to a safe location to sort out the usual affair of trading insurance information and filing police reports.

Contributing to the problems of congestion also include the first responder's policies of blocking at least two lanes to allow the emergency personel to work more safely.  (Anecdotally, I once spent an hour and a half in traffic only to discover that 2 out of 3 available lanes had been shut down while another bonehead went to a tire store to get a new tire.)

I'd like to see a law that charges drivers $10/minute for delays they incur from being stupid, not maintaining their vehicles, or $20/minute for drivers that do both.  You'd see flats get changed faster.

Having said that, sometimes, traffic delays are inavoidable.  Add in exit only lanes and people that aren't moving at the speed of traffic trying to get out of them, and that compounds the problem.  

A good example is when my employer's truck caught fire, while I was towing a gooseneck trailer with it, resulting in a complete electrical failure; without signals or a horn, I forced myself to the right as much as possible, praying for a shoulder to stop on, and discovered the dillema of deciding whether I was safer in the truck with the risk of smoke inhalation, or getting out as severly pissed off drivers in Christmas traffic drove around the burning vehicle like it was a speedway.  I blocked two lanes, a shoulder and an entrance ramp, three lanes by the time fire trucks arrived, leaving only the left shoulder open, all because drivers too intent on getting to a nearby mall weren't going to let me over despite an obvious emergency,  because they needed to get out of an exit only lane.  News reports say I backed traffic up for 7-8 miles.

And accidents happen in the same spot everyday because some traffic interchanges are poorly designed.  Short ramps, merging together, create a bottle neck that can stretch for miles.  Dallas has it's fabled "Deadman's curve" which is hair raising for locals as well as non-locals suddenly dropping out of an already complicated interchange system, only to have to slow below 20 Mph to make a 90 deg left turn.  Add in that the two lanes entering Deadman's curve are both exit only lanes, coming out of an interchange known as the "Mixmaster," and you have an instant jam up before it, which gets worse when some hothead guns it down the ramp and is taken totally by surprise when he hits the turn.  And the K-wall.

Bad manners, bad driving, the ease of getting a license, bad maintenance, simple stupidity, bad engineering and bad planning of road maintenance, more cars, and the like all contribute to the growing traffic h**l we all face.

JT

Answer 8

A simple answer to this is that no two people are the same, therefore they react differently to the exact same situation.

This accounts for the fact that some people drive exactly the speed limit, some just over, and some just under.

Some people slow down at every occurrence of something out of the ordinary, while others only slow down if they think it necessary judging by the situation.

And, YES, everyone gawks (rubber necks) at accidents.  It's just that some people slow down and others do really stupid things like come to almost a complete stop.

The difference in a stock car race and normal traffic is that the racers all have one thing in mind - get to the end in first place.  They also have about the same skill and experience in driving.  With normal commuters, many have absolutely no place to go and no business being on the road most of the time.  And, as we all know, many drivers just cannot drive!

As far as repeat accidents, there is usually a reason that they keep occurring in the same places.  Sometimes the road is bad.  Or it could be that there's an obstacle that distracts drivers or slows them down.  The ripple effect back through traffic is not linear, meaning that the reaction time shortens the further back through the crowd of cars it goes.  This accounts for the fact that the original car that slammed on the brakes almost never hits anything, sometimes not even the second car, but the third car almost never stops in time and the fourth is almost guaranteed to take the rear of the third car every time!