http://www.economist.com/science/displaystory.cfm?story_id=12202559
Queuing conundrums
Sep 11th 2008
From The Economist print edition
Strange as it might seem, closing roads can cut delays
DRIVERS are becoming better informed, thanks to more accurate and timely advice on traffic conditions. Some services now use sophisticated computer-modelling which is fed with real-time data from road sensors, satellite-navigation systems and the analysis of how quickly anonymous mobile phones pass from one phone mast to another. Providing motorists with such information is supposed to help them pick faster routes. But the latest research shows that in some cases it may slow everybody down.
Hyejin Youn and Hawoong Jeong, of the Korea Advanced Institute of Science and Technology, and Michael Gastner, of the Santa Fe Institute, analysed the effects of drivers taking different routes on journeys in Boston, New York and London. Their study, to be published in a forthcoming edition of Physical Review Letters, found that when individual drivers each try to choose the quickest route it can cause delays for others and even increase hold-ups in the entire road network.
The physicists give a simplified example of how this can happen: trying to reach a destination either by using a short but narrow bridge or a longer but wide motorway. In their hypothetical case, the combined travel time of all the drivers is minimised if half use the bridge and half the motorway. But that is not what happens. Some drivers will switch to the bridge to shorten their commute, but as the traffic builds up there the motorway starts to look like a better bet, so some switch back. Eventually the traffic flow on the two routes settles into what game theory calls a Nash equilibrium, named after John Nash, the mathematician who described it. This is the point where no individual driver could arrive any faster by switching routes.
The researchers looked at how this equilibrium could arise if travelling across Boston from Harvard Square to Boston Common. They analysed 246 different links in the road network that could be used for the journey and calculated traffic flows at different volumes to produce what they call a “price of anarchy” (POA). This is the ratio of the total cost of the Nash equilibrium to the total cost of an optimal traffic flow directed by an omniscient traffic controller. In Boston they found that at high traffic levels drivers face a POA which results in journey times 30% longer than if motorists were co-ordinated into an optimal traffic flow. Much the same thing was found in London (a POA of up to 24% for journeys between Borough and Farringdon Underground stations) and New York (a POA of up to 28% from Washington Market Park to Queens Midtown Tunnel).
Modifying the road network could reduce delays. And contrary to popular belief, a simple way to do that might be to close certain roads. This is known as Braess’s paradox, after another mathematician, Dietrich Braess, who found that adding extra capacity to a network can sometimes reduce its overall efficiency.
In Boston the group looked to see if the paradox could be created by closing any of the 246 links. In 240 cases their analysis showed that a closure increased traffic problems. But closing any one of the remaining six streets reduced the POA of the new Nash equilibrium. Much the same thing was found in London and New York. More work needs to be done to understand these effects, say the researchers. But even so, planners should note that there is now evidence that even a well intentioned new road may make traffic jams worse.
No... I think ERP works. I have a number of friend refrain from driving to work in ERP area due to the high cost. Imagine ERP is cheap and they take up drving to ERP area. Jam will be worst. In fact, I think LTA shall rise ERP fee even further by 50% to deter even more people driving into CBD area to ease traffic woes better.
Only the vey rich will drive in. Those middle class may think twice going in. Look at MRT record passenger shows more people take MRT to CBD area to work than drive in.
Of cos, best is to drive a weekend car.
ERP do works... just not very effective.
Originally posted by zenden9:No... I think ERP works. I have a number of friend refrain from driving to work in ERP area due to the high cost. Imagine ERP is cheap and they take up drving to ERP area. Jam will be worst. In fact, I think LTA shall rise ERP fee even further by 50% to deter even more people driving into CBD area to ease traffic woes better.
Only the vey rich will drive in. Those middle class may think twice going in. Look at MRT record passenger shows more people take MRT to CBD area to work than drive in.
Of cos, best is to drive a weekend car.
I have no issues with implementing ERP in CBD area. After all, that's where traffic can potentially be the most congested.
But ERP on expressways? ERP in Toa Payoh? ERP in other non-CBD areas, is total rubbish.
especially peak hours
Originally posted by zenden9:No... I think ERP works. I have a number of friend refrain from driving to work in ERP area due to the high cost. Imagine ERP is cheap and they take up drving to ERP area. Jam will be worst. In fact, I think LTA shall rise ERP fee even further by 50% to deter even more people driving into CBD area to ease traffic woes better.
Only the vey rich will drive in. Those middle class may think twice going in. Look at MRT record passenger shows more people take MRT to CBD area to work than drive in.
Of cos, best is to drive a weekend car.
What you are saying is that ERP works by marginalising the poor to take public transport. To a certain extent, ERP may deter some from driving to work. However, as we can see as driver on the road, ERP DOES NOT reduce traffic flow at all. This is a real problem and not one just to condemn the system as it is costly for us drivers. If you would bother to look around, the problem of traffic jams are very real. It is a daily occurance.
If ERP are able to reduce traffic jams, I would think that lesser of us would complain day in day out. But ERP does not solve anything, resulting in all of us lesser mortals to think of it as a myth.
It is common logic that if our dearest government wants to collect more taxes from cars, they would at last have to give us back something in the form of better network of roads (not a white elephant like KPE), wider road, reasonable laws to keep out those farking road hoggers who drive at 90km/hr at the 1st lane and does not think that giving way to vehicles to overtake is correct as they are within the speed limit. Idiotic motorcycles who take up 2-3 lanes at the same time. Lorries who overtake you then slow to almost a complete halt, etc. It is because of people like these who caused a huge empty space on the road and refuses to let others fill up the space. If you can imagine. Should we be able to fill up more of the road, we can move more vehicles. Shouldn't our stupid "traffic police" do more than just make themselves invisible and take photos to earn commission? If need be, we can employ our own photographer to take nicer pictures of our cars. Thank you.
There are simply easier ways to solve our traffic problems. It is just that our dearest government who is so UP THERE that they chose to employ a more profitable one.
P.s. there are no elements of slender nor threat. Please do not sue me. I am just one of the many unemployed out there trying to survive while you sit on your plush cushions.
its just another form of tax revenue for the govt lah...
take it this way, in e past it was expensive ownership but cheaper in usage.. now it's just the other way round
honestly it isn't just the ERP alone, it's e ownership policy as well. to be honest, all these jams ironically made buses to be severly delayed on the road these days
dun use bus lane, buses dun travel straight forever, at some junction they need to filter right to proceed to their destination
Bus lane is another bane to the traffic jam problem.
Since they already have their exclusive lane then stick to it. Make adjustment for all their turnings from there. They are so freaking big size. Fark it when they dont care about the cars and just filter out because they wont get hurt due to their farking size.
Can you imagine how irritating is it that some roads only have 3 lanes? One is reserved for the buses cuz they pay more road tax, 1 for going straight and 1 for turning? Fark, I would take after your surname if there are no traffic jams, Idiotic piece of shiet
Originally posted by bratpig:Bus lane is another bane to the traffic jam problem.
Since they already have their exclusive lane then stick to it. Make adjustment for all their turnings from there. They are so freaking big size. Fark it when they dont care about the cars and just filter out because they wont get hurt due to their farking size.
Can you imagine how irritating is it that some roads only have 3 lanes? One is reserved for the buses cuz they pay more road tax, 1 for going straight and 1 for turning? Fark, I would take after your surname if there are no traffic jams, Idiotic piece of shiet
if they dun do it, would you give way? even those yellow boxes meant for buses to exit e bus bay are oftenly occupied by cars these days.
exclusive lane and stick to it? so those buses along Whitley Rd (From PIE) turning to Bt Timah Rd, so you going to tell them from left lane make a sharp 90 degree turn across e junction to get to Bt Timah Rd? continue on dreaming if bus routes are forever straight
public buses have priority over cars on e road.. imagine you delay 1 bus for 2 mins, meaning to say you've wasted 3 man hours if there's 90 ppl onboard.
and we have people here who have the cheek to blame buses for being late at every fare hike
To sum up, ERP only benefits they who has money making as their top priority. It is not proven that ERP ease the traffic during peak hours. To them is money money money to their pockets, money is the rich men's world! ha ha ha!
Vote lor, vote some more for pay and pay and pay till you die! Now even if you die, no worry, they still would like to earn money, just buy casket from NTUC Casket. Ha ha ha, what have they not ventured into to make money out of the people???
Look Mister, we are not here to discuss about your precious buses. I don't give a hoot. Yes, some may not give way, some may. THE POINT IS PEOPLE CAN GET KILLED HERE!!! It is the same rule everywhere. If you want to filter lane, you jolly well wait for people to give way to you or when traffic is clear. You dont just turn out as if it is your mother's road.
Anyway, if OOT, I'm so sorry. Go back to discussing buses elsewhere. I think you all have a forum specially for that purpose.
Ha ha ha, what have they not ventured into to make money out of the people???
Taken over by greed.
And the people in Singapore are too meek and too brainwashed to stand up against them, so they do what they can, like pay highest pay, erect ERPs.
Originally posted by Ah Chia:Taken over by greed.
And the people in Singapore are too meek and too brainwashed to stand up against them, so they do what they can, like pay highest pay, erect ERPs.
Yes, it is partially the fault of the people who have gotten them to what they are today. They can just simply ignore the public's voice to go on to do things to meet their self serving agenda.
As politicians they are to serve people, fear people, meet people's needs, respect the choice of the people and place public service as top priority but what we seee it is the opposite that is happening. the evil senile selfish bastard lky has made this so to benefit himself and the party. He makes people fearful of him and gang. can't wait for his demise.
Yes, it is partially the fault of the people who have gotten them to what they are today.
They also managed to brainwash people that peaceful protests(like SDP) is somehow bad.
Some people in this forum are taken in by this type of propaganda.
Politics are never meant to be clean in the first place. It has been the case since our ancestors...It is not going to change overnight. People will never have the power to change.
Originally posted by Ah Chia:They also managed to brainwash people that peaceful protests(like SDP) is somehow bad.
Some people in this forum are taken in by this type of propaganda.
I have no qualms about peaceful protests for good cause.
It is the fault of the evil old senile dictator that people are so brainwashed. Many in singapore take it that protest is bad. Peaceful protest is acceptable but not the unruly ones.
old man lee is the curse of the family, ha ha ha!
Originally posted by bratpig:Politics are never meant to be clean in the first place. It has been the case since our ancestors...It is not going to change overnight. People will never have the power to change.
ha ha ha, your last statement is overstated. Saddam Hussein was overthrown, so ????
LOL. It took the US Army to "overthrow" him dude.
Maybe if we were to appeal to the USA for help? Haha. No chance, our dear CSJ has done it before.
Just to add in. I'm very sure our ruling party monitors the internet religiously. In fact, they should know where they stand even in the absence of polls unlike other countries. Why are they still so oblivious to their current popularity level?
Originally posted by bratpig:LOL. It took the US Army to "overthrow" him dude.
Maybe if we were to appeal to the USA for help? Haha. No chance, our dear CSJ has done it before.
ha ha ha. with the old one around difficult. may be now he is negotiating with hell to have a communication channel with singapore after he arrives in hell to live there for good.
Originally posted by Fantagf:
ha ha ha. with the old one around difficult. may be now he is negotiating with hell to have a communication channel with singapore after he arrives in hell to live there for good.
LOL. Erm, maybe the deal doesn't involve any travelling at all?
Originally posted by bratpig:LOL. Erm, maybe the deal doesn't involve any travelling at all?
Travelling me? oh blind me!! the dead spirit will appear in seconds to the place. May be he will be able to view what is happening in sg from his computer there.
In anyway, the deal is done. People are talking big about exercising our rights come 2011 or what shiet. However, we have failed to realise that some are just talking cock, some are too young to vote and some are simply too afraid of changes.
No venture no gain. If nobody dare to take the first step out, we would only have ourselves to blame. Afterall, we can't expect things to change status quo. Up there will not see the need to change their SOP cuz we mortals are deemed too meek for them.
Not to forget. FTs getting PRs is for a reason. Wait till they get their voting rights.
Saddam Hussein was overthrown
Ferdinand Marcos is probabaly a better example.
http://en.wikipedia.org/wiki/People_Power_Revolution
The people overthrowed the despotic Marcos regime in 1986, next year 1987, our Lee regime came up with the "marxist" "plot".
http://www.singapore-window.org/
Seems like the events in the Philippines really spooked the old dog.
Must strike first.