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Post Info TOPIC: Trigger Event and Typical Day Traffic


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Trigger Event and Typical Day Traffic


Trigger Event and Typical Day Traffic.

Trigger Event

Let us consider a scenario of 6 former motorists who have sold or otherwise disposed of their cars to commute by taxi and each goes to the CBD in the morning at the interval of 30 minutes. And assuming that the traffic is free-flowing and it takes 30 minutes for a taxi to travel to and fro and in the evening, similarly they return home at the same interval of 30 minutes. The road usage and the state of the roads are exactly the same whether the 6 former motorists commute by a taxi or 6 motorists commute by 6 cars travelling at different time intervals.

Multiply this by 50,000. We have 50,000 taxis and 300,000 former motorists. The road usage and the state of the roads are also exactly the same whether the 300,000 former motorists commute by taxis or 300,000 motorists commute by 300,000 cars travelling at different time intervals.

Now, if these 300,000 commuters are not former motorists. They are motorists with 300,000 cars. And then something happens (a trigger event), all of them want to go to the CBD at 7.00am. Would there be massive traffic congestion? On the other hand, if they are taxi commuters, they cannot do that. Whatever the event, 50,000 taxis on the road remain 50,000 taxis on the roads.

When motorists are converted into taxi commuters, they lost their ability to cause congestion. So taxi commuters are preferred to motorists from the congestion management point of view.

The trigger event scenario reveals the following important characteristics of taxi commuting:

(1) The taxi imposes a trip staggering on the taxi commuters

The taxi imposes a trip staggering on the taxi commuters as the taxi has to turn around in order to pick up the next passenger. Anyone who wants to commute by taxi must accept this de facto trip staggering. In other words, once a motorist decides to commute by taxi, it means that the current taxi waiting time is acceptable to him and he has to catch the taxi at a time when it is available. If he cannot meet these conditions, he cannot be a taxi commuter. He has to find a means to enable him to carrying on travelling by car.

(2) The taxi commuter cannot cause congestion whereas the motorist can.

This is because the taxi commuter has to wait for the taxi whereas the motorist could drive his car at will. When enough motorists decide to drive on the same road at the same time, we have congestion. So congestion is best managed by reducing the number of private car owners.

Typical Day Traffic

(1) The typical day traffic is not a fixed constant.

The commuters, especially the motorists, do change their travelling patterns in response to any change in the road conditions. A good example is when the ERP is imposed for the first time on a road. See point (2) below.

(2) The taxi trip staggering causes the effective spreading of peak demand and it could cause the dramatic easing of congestion.

Now let us consider a scenario where there are 300,000 taxi commuters and 50,000 taxis, and where, at the beginning at each time interval of 30 minutes, there are 25,000 taxi commuters. So for the 6 time intervals from 5.00pm, there are a total of 150,000 taxi commuters (say 25,000 at 5.00pm, 25,000 at 5.30pm .... 25,000 at 7.30pm). This would leave us with a total of 150,000 (300,000-150,000) floating commuters. And if these 150,000 floating commuters first try to catch their taxis at 6.30pm, we would, on day 1, have 175,000 taxi commuters wanting to catch taxis at 6.30pm. Since there are only 50,000 taxis, only 50,000 taxi commuters would have taxis, the rest of them (125,000) have to wait for the taxis to turn around. After some time, many taxi commuters would notice that if they leave their home or office half another hour earlier or later than 6.30pm, there would be more taxis for them. So the spreading would begin until the taxi commuters are more or less evenly spread to the various time intervals in both directions. A similar phenomenon is observed when the ERP is introduced for the first time on a road. Many motorists would adjust their travelling time to either before the ERP is on or after it is off when they reach the ERP gantry.

If after some time after the spreading has stopped, there are more than 50,000 taxi commuters wanting to catch a taxi, say at 7.00pm, then the taxi fleet may have to be increased in batches to cater to all the taxi commuters, assuming for the purpose of this scenario, the increase in the number of taxis is possible.

So instead of having 300,000 private cars travelling randomly during the evening peak causing massive congestion, the taxi trip staggering could spread out the peak demand evenly during the peak period between 5.00pm and 8.00pm. This would result in the dramatic easing of congestion.

Now let us have a closer look at the nature of our traffic congestion. It is normally caused by too many vehicles at the same time on the roads where the congestion occurs. And one category of vehicles stands out: private cars. There were 421,904 (64.25%) private cars in 2006 (Brief 2007) out of a total vehicle population of 656,637, excluding motorcycles. So the main contributors to the congestion are private cars and many motorists drive because of the inefficient taxi service. When the taxi service is efficient, many motorists would take taxis instead.

If one additional taxi removes one private car from the road, there would be no increased in congestion as the result of the additional taxi. If it removes 2 private cars, there will be an improvement in the congestion. If it removes 3 private cars, there will be further improvement in the congestion. If it could remove 6 private cars, there will be a dramatic improvement to the traffic congestion as 50,000 taxis could remove 300,000 private cars from the roads.

Do note here that traffic congestion is usually caused by too many vehicles, especially cars, on the roads in a certain area at a particular point of time. 50,000 taxis cruising on the roads would remain 50,000 no matter what happens, unlike the 300,000 cars they have replaced. There could be a trigger event, personal or otherwise, when all or many of the 300,000 cars are on the roads at the same time. When this happens, we have massive traffic congestion.

In other words, a taxi cannot appear simultaneously at 6 places at the same time on the same road whereas the 6 cars it has replaced could, if it could remove 6 cars from the roads. This is a critical difference between a taxi and a car in the context of congestion management.

(3) Road usage efficiency rockets upwards

When the traffic is free-flowing, the road usage efficiency rockets upwards. A taxi or car trip of 10km from the CBD to the outskirt during the peak periods that takes 30 minutes or more because of the congestion could now be completed in less than 15 minutes with the vehicle travelling at about 60 kmph.

The current taxi apparent shortage intensity is artificially created, especially by the very high call booking fee and the ERP charges on taxis. So we may actually need far less than 50,000 taxis to have free-flowing traffic in Singapore.

And this is without factoring in the number of commercial vehicles that are actually being used some of the time as a personal transport in lieu of a car or taxi.

(4) Elimination of car park full induced congestion

Quite frequently at popular shopping centres, offices and places of interest, we do find congestion caused by many stationary vehicles on the roads waiting to go into the full car park. And many among those who are causing the congestion are motorists. If only many of these motorists are taxi commuters, the congestion could have been eliminated or greatly reduced.

(5) Many people drive because of notoriously bad taxi service

In our case before the recent taxi fares hike, many people drive because of our notoriously bad taxi service with taxis hiding from passengers or refusing to pick them up keeping passengers at times waiting for hours. So there already exists a huge pool of potential taxi commuters among the motorists waiting for a reliably efficient taxi service.

An efficient taxi service, where the taxi commuter can get a taxi within 10 minutes whether at the taxi stand, flagging it down on the road or calling for it on the phone, would certainly convert many motorists to taxi commuters. A less efficient one with a 15-minute wait would still convert many motorists to taxi commuters, albeit lesser than a more efficient one.

The differential between the costs of owning and using a car and the taxi fare is crucial to many other motorists deciding whether to commute by taxi or by car. The recent hefty increases in taxi fares would induce many people to buy cars and worsen the congestion on the roads.

(6) An attractive bonus for the former motorists

As former motorists, these taxi commuters no longer need season parking near their homes and places of work. This could easily save them S$200.00 a month each. Then there are also the savings of paying for parking lots at the other places they visit, and of the time and hassle looking for a parking lot.

(7) ERP only transfer the peak demand and congestion elsewhere

In this connection, do note that high ERP charges do not effectively spread peak demand. Instead they transfer the peak demand and congestion to other roads or to the periods when the ERP is off.

Moreover, so long as the motorist is in possession of a car, there is nothing to stop him to travel during the peak, if he has a reason to travel (a personal trigger event) and willing to pay the current ERP charges. So at best, this means that on some days the ERP at a particular charge works and that on some other days it does not, depending on whether there are enough motorists wanting to travel during the peak period.

(8) High ERP charges are socially divisive, artificially inflationary and unjustifiably depriving many people the use of a modern transport convenience

High ERP charges raise artificially the costs of doing business and of living. They, by themselves, do not provide an acceptable alternative public transport to the motorists whereas an efficient taxi service does. They deny many Singaporeans the use and the benefits of the automobiles on congestion grounds.

As a long-term solution to congestion, ERP, by itself, is not only ineffective, but also highly socially divisive, artificially inflationary and unjustifiably depriving many people the use of a modern transport convenience when the actual problem is congestion and when an efficient taxi service would have made Singapore congestion-controlled.

(9) Super high ERP charges would make our roads underutilized

Super high ERP charges everywhere would get rid of the congestion, but our roads would become underutilized and, perhaps, even white elephants.

(10) ERP could be useful under certain circumstances

However, ERP could be useful, when there is an urgent need to divert traffic for some reasons.

(11) Like the ERP, surcharges do not solve problems on the whole.

For a surcharge to be effective, it has to be high enough to attract taxis from other areas. They simply transfer the taxi shortage to other places, just like ˇ°digging one hole to cover anotherˇ±. Additional taxis are simply required for areas where they are not enough.

When taxi drivers prefer to hide from passengers or to cruise around empty waiting for booking calls or for a surcharge to be imposed instead of going to the areas where they are needed, it is a clear symptom of a seriously malfunctioned taxi service.

(12) The taxi commuter has no push factor to commute unless it is really needed.

The taxi commuter only pays for the taxi fare when he travels, with the taxi fare reflecting his full costs of commuting unlike the motorist whose ownership of the car may cost him up to $30.00 day whether he drives his car or not. So for the motorist, there is a tendency to make better use of his ˇ°investmentˇ± and therefore for him to increase road usage and to cause more congestion than what is really needed.

(13) Taxis match the needs of the motorists far better than the MRT and buses

Among the components of the Singapore public transport system, the taxi service is the one that matches the needs of the motorists far better than the MRT and buses. So it is far easier to persuade a motorist to commute by taxi than by MRT or bus. With Singapore's excellent roads and extremely high mobile phone ownership rate, the most costly and important ingredients for an efficient taxi service are already in place. Let us make better use of our investments in these two areas.

(14) A gross savings of S$20,000,000,000.00 per 10 years for Singapore as a whole.

If owning a car costs a motorist including interest, on the average S$80,000 net, the 250,000 net cars removed by the 50,000 taxis would save Singapore as a whole S$20,000,000,000.00 every 10 years, if the average car has a life span of 10 years.

(15) Huge reduction in the need for car parks and parking lots.

All vehicles need parking spaces, especially one at home and one at work or at any other place where it is parked for a reason, except the taxis when they are in service. So if many motorists give up their cars for taxis, a lot of parking spaces could be freed or eliminated.

If, on the average, a car needs 2 parking spaces of 6.50 sq m (69.97 sq ft) each including the access ways, the 250,000 cars removed would free or eliminate 3,250,000 sq m (34,983,000 sq ft) of parking space.

Related Links
ERP only reduces congestion temporarily



-- Edited by ProTaxi at 05:07, 2008-08-05

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