About Speed Cameras ?

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umit
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Re: About Speed Cameras ?

Post by umit » Fri Jun 26, 2009 2:08 pm

Tiwaz wrote:
Karhunkoski wrote:
Tiwaz wrote: Why slowing down on motorways is bad is that it causes traffic jams.
Understand your logic, but I don't think the chaps mean a full-on braking session to allow someone to join from the ramp. I think what they mean is slightly easing off the throttle, perhaps reducing speed by 5-8 Km/h, in order that someone can join the flow easily. If you don't let them in, the cars behind get nervous about whether the joiner will try and muscle in anyway, so to avoid this they brake themselves, thus causing the jam that you describe above.
You forget that slowing down in dense traffic multiplies with each car if there is no sufficient distance between vehicles.

First car slows down 5-8km/h, next has to slow down 8-12km/h, one behind it has to slow down 12-15km/h and so forth until either safety distance has managed to eat the loss of speed, you run out of cars or total jam is created.
Rubbish! While driving at 80 km/h reducing the speed by 5-10 km/h for a few seconds and then recovering to original speed would NEVER cause a traffic jam. This disturbance would be absorbed by not more than 3 or 4 cars and the 5th car would never feel it. That "butterfly effect" would happen at very slow speeds and bumper-to-bumber flows...

But, later on that one car you let join in front of you would be the last car to pass on the green lights and you stay... That's quite annoying, innit? :wink:



Re: About Speed Cameras ?

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onkko
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Re: About Speed Cameras ?

Post by onkko » Fri Jun 26, 2009 2:23 pm

umit wrote: Rubbish! While driving at 80 km/h reducing the speed by 5-10 km/h for a few seconds and then recovering to original speed would NEVER cause a traffic jam.
Ok my eyes and what i have feeld are wrong. One breaked in front and i were about 10th and i had almost stop. That was of course wrong and by your laws i would have hit on trunk whoever drove front of me.
Get a drivers licence and drive few years and then come to tell us how its happen, with proofs of course because your way doesnt seem to be understandable way.
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sinikala
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Re: About Speed Cameras ?

Post by sinikala » Fri Jun 26, 2009 2:39 pm

Tiwaz wrote:Finnish cultural tradition.
An oxymoron which ranks alongside "American intelligence" <--- see what I did there?!
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onkko
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Re: About Speed Cameras ?

Post by onkko » Fri Jun 26, 2009 2:44 pm

sinikala wrote:
Tiwaz wrote:Finnish cultural tradition.
An oxymoron which ranks alongside "American intelligence" <--- see what I did there?!
Ok, whole europe is oxymoron then... Sure we dont have any traditions, you just whine about something you dont like in home. We are all same...
Let forget that finns have been here only 4000 years and that some invader thinks hes better..
Caesare weold Graecum, ond Caelic Finnum

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Karhunkoski
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Re: About Speed Cameras ?

Post by Karhunkoski » Fri Jun 26, 2009 2:58 pm

Tiwaz wrote: How about just shutting up and accepting that here things which you consider as epitome of good manners are considered irrelevant to good manners and good manners are defined by Finnish cultural tradition.

How about realising that many many Finns who have spent extended periods of time living abroad, really do think that most Finns lacks manners, in comparison to where they've lived. I know quite a few friends and family who have said just this. Of course Tiswas, they must have been telling porkies :roll: The fact doesn't bother me greatly, but your arrogant and introverted junttiness does. I have a choice whether to live in Finland or not, but I live here. You're just here.

You can reply if you wish, but I promise not to read any more of your angry drivel for a few days.
Political correctness is the belief that it's possible to pick up a turd by the clean end.

umit
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Re: About Speed Cameras ?

Post by umit » Fri Jun 26, 2009 4:07 pm

onkko wrote:
umit wrote: Rubbish! While driving at 80 km/h reducing the speed by 5-10 km/h for a few seconds and then recovering to original speed would NEVER cause a traffic jam.
Ok my eyes and what i have feeld are wrong. One breaked in front and i were about 10th and i had almost stop. That was of course wrong and by your laws i would have hit on trunk whoever drove front of me.
Get a drivers licence and drive few years and then come to tell us how its happen, with proofs of course because your way doesnt seem to be understandable way.
Ok. Here is proof, let's do some math:

80 km/h = 80.000m / 3600 sec = 22,2 m/sec It means you travel 22,2 meters every second...
70 km/h = 70.000m / 3600 sec = 19,4 m/sec

If you decrease your speed from 80 to 70 for 10 seconds (normally it shouldn't take that long):

(22,2 - 19,4) * 10 = 28 m You will be 28 meters (Actually, it is slightly less than that, because you slow down gradually) behind of your original/"supposed to be" position.

According to "3 seconds follow distance rule" you need to give 22,2 * 3 = 66,6 meters of distance between yourself and the car in front of you...

Result: Even if the car behind the slowing-down-car doesn't change its speed, the distance between them would be 66,6 - 28 = 38,6 meters after 10 seconds... In my opinion, if someone is following the traffic ahead carefully, one driver can absorb this distance.

But let's stick with my original claim that 4 drivers to absorb: 28 m / 4 = 7 meters (the distance that every driver has to sacrifice from his following distance.

It can be achieved by slowing down from 80 to 75 for 5 seconds!

I think in your case it was a real bad luck that 10 idiots were driving in a row!!!

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Bubba Elvis XIV
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Re: About Speed Cameras ?

Post by Bubba Elvis XIV » Fri Jun 26, 2009 4:12 pm

Wow!!!! My dorkdar went off the scale then :wink:
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Karhunkoski
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Re: About Speed Cameras ?

Post by Karhunkoski » Fri Jun 26, 2009 4:49 pm

Shhhh Bubs, Finland needs intelligent immigrants. But what will happen when they outsmart the locals. :lol:
Political correctness is the belief that it's possible to pick up a turd by the clean end.

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Bubba Elvis XIV
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Re: About Speed Cameras ?

Post by Bubba Elvis XIV » Fri Jun 26, 2009 4:59 pm

Karhunkoski wrote:Finland needs intelligent immigrants.
What happens when we/you get loads of 'em? Do I have to leave? :lol:
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Karhunkoski
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Re: About Speed Cameras ?

Post by Karhunkoski » Fri Jun 26, 2009 5:06 pm

Bubba Elvis XIV wrote:What happens when we/you get loads of 'em? Do I have to leave? :lol:
Nope, there's still a need to learn how to

- say "language" without it rhyming with "sandwich".
- understand that toinen sometimes means "another" and sometimes it means "the other"
- use "at", as in "at the bus stop", not "on the bus stop".


But your list is probably longer than mine.
Political correctness is the belief that it's possible to pick up a turd by the clean end.

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Bubba Elvis XIV
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Re: About Speed Cameras ?

Post by Bubba Elvis XIV » Fri Jun 26, 2009 5:22 pm

You missed it...Perhaps you'll be asked to leave too :lol: :wink:
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onkko
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Re: About Speed Cameras ?

Post by onkko » Fri Jun 26, 2009 7:15 pm

umit wrote:
onkko wrote:
umit wrote: Rubbish! While driving at 80 km/h reducing the speed by 5-10 km/h for a few seconds and then recovering to original speed would NEVER cause a traffic jam.
Ok my eyes and what i have feeld are wrong. One breaked in front and i were about 10th and i had almost stop. That was of course wrong and by your laws i would have hit on trunk whoever drove front of me.
Get a drivers licence and drive few years and then come to tell us how its happen, with proofs of course because your way doesnt seem to be understandable way.
Ok. Here is proof, let's do some math:

80 km/h = 80.000m / 3600 sec = 22,2 m/sec It means you travel 22,2 meters every second...
70 km/h = 70.000m / 3600 sec = 19,4 m/sec

If you decrease your speed from 80 to 70 for 10 seconds (normally it shouldn't take that long):

(22,2 - 19,4) * 10 = 28 m You will be 28 meters (Actually, it is slightly less than that, because you slow down gradually) behind of your original/"supposed to be" position.

According to "3 seconds follow distance rule" you need to give 22,2 * 3 = 66,6 meters of distance between yourself and the car in front of you...

Result: Even if the car behind the slowing-down-car doesn't change its speed, the distance between them would be 66,6 - 28 = 38,6 meters after 10 seconds... In my opinion, if someone is following the traffic ahead carefully, one driver can absorb this distance.

But let's stick with my original claim that 4 drivers to absorb: 28 m / 4 = 7 meters (the distance that every driver has to sacrifice from his following distance.

It can be achieved by slowing down from 80 to 75 for 5 seconds!

I think in your case it was a real bad luck that 10 idiots were driving in a row!!!
http://www.sciencedaily.com/releases/20 ... 151550.htm

"Such phantom jams can form when there is a heavy volume of cars on the road. In that high density of traffic, small disturbances (a driver hitting the brake too hard, or getting too close to another car) can quickly become amplified into a full-blown, self-sustaining traffic jam."

"Flynn and Kasimov worked with MIT math instructors Jean-Christophe Nave and Benjamin Seibold and professor of applied mathematics Rodolfo Rosales on this study."

So of course youre wiser than them...
Caesare weold Graecum, ond Caelic Finnum

umit
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Re: About Speed Cameras ?

Post by umit » Fri Jun 26, 2009 8:28 pm

http://www.sciencedaily.com/releases/20 ... 151550.htm

"Such phantom jams can form when there is a heavy volume of cars on the road. In that high density of traffic, small disturbances (a driver hitting the brake too hard, or getting too close to another car) can quickly become amplified into a full-blown, self-sustaining traffic jam."

"Flynn and Kasimov worked with MIT math instructors Jean-Christophe Nave and Benjamin Seibold and professor of applied mathematics Rodolfo Rosales on this study."

So of course youre wiser than them...
Don't make cross references to the articles you don't/can't understand... There is nothing contradicting between my calculations and that article.

http://en.wikipedia.org/wiki/Traffic_flow


In a free flowing network, traffic flow theory refers to the traffic stream variables of speed, flow, and concentration. These relationships are mainly concerned with uninterrupted traffic flow, primarily found on freeways or expressways.[1] "Optimum density" for U.S. freeways is sometimes described as 40–50 vehicles per mile per lane.[citation needed] As the density reaches the maximum flow rate (or flux) and exceeds the optimum density, traffic flow becomes unstable, and even a minor incident can result in persistent stop-and-go driving conditions. The term jam density refers to extreme traffic density associated with completely stopped traffic flow, usually in the range of 185–250 vehicles per mile per lane.

Let's turn back to our example: We have drivers travelling at 80 km/h and keeping 66,6 meters of distance each other... 1 mile = 1609m. 1609 / 66,6 = 24 cars per mile! Much lower than optimum density for US freeways... Even a hundred of idiots like you can't cause a traffic jam under that circumstances :twisted:

From the article you referred:

The team tackled the problem last year after a group of Japanese researchers experimentally demonstrated the formation of jamitons on a circular roadway. Drivers were told to travel 30 kilometers per hour and maintain a constant distance from other cars. Very quickly, disturbances appeared and a phantom jam formed. The denser the traffic, the faster the jams formed.

You see, 30 km/h not 80!!! Because, traffic jams don't happen at high speeds.
umit wrote:That "butterfly effect" would happen at very slow speeds and bumper-to-bumber flows...
The reason is: In theory, you can travel at 80 km/h bumber-to-bumber. However, in practice even if you are not aware of 3 seconds rule you put a distance between you and the car in front of you. The higher the speed the longer the distance, thus less density and no traffic jam...

Onkko please make me and yourself a favor and stop trying to overwhelm my comments, you are going deeper into swamp while struggling to come out ;)

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onkko
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Re: About Speed Cameras ?

Post by onkko » Fri Jun 26, 2009 9:19 pm

You are assuming all drivers drive like math and all keep safety distances and.. thats where you fail.
Youll see when you see jams created by "stupid people" in 80 area.

"Because, traffic jams don't happen at high speeds." Yeah right, tell that to autobahn drivers.
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FIRAT
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Re: About Speed Cameras ?

Post by FIRAT » Fri Jun 26, 2009 9:22 pm

onkko wrote:
Bubba Elvis XIV wrote:My real name is Gustav Gustavsson...
Obviously swedished name of Kalle Kallenpoika!
I would say Kalle Kallenpoika is Finnished from Swedish as many things and words are from Swedish in Finnish.
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