Maximal flow

The View From Taft
Dennis L. Berino

Posted on May 26, 2016

It is still summer, although the much needed rain is slowly manifesting itself in the country. Since almost half of the metro’s population is of school age and on vacation, people expect a reduction in the extreme traffic that they suffer daily except on Sundays. Sunday is the time when most weary people stay home to revive themselves from the daily rigors of traffic.

Maximal flow is a quantitative technique that can help us alleviate traffic. It is a network model with a source node (point of entry) and an output node (point of exit), and helps in determining the maximum flow of objects (e.g., cars, planes, fluids, and electricity) that can enter the network at the source node, flow through the network, and exit at the output node in a given time.

Metro Manila is one big traffic network, with vehicles entering its borders daily. With a land area of a little over 600 sq. km. and a population of 12 million at night and 15 million during the day and with about 40% of the country’s registered motor vehicles within its boundaries, it is a maximal flow nightmare. Just like death and taxes, traffic is certain to happen in the metropolis daily. We can, however, implement certain strategies that can decrease traffic.

The elevated connector road between NLEx and SLEx being constructed now is a good solution to increase the flow of traffic in the city. Its flaw, however, is its perspective of moving vehicles, not people. It basically serves the car-riding public, but considering that only 20% of the city’s people have cars, the 80% may not be directly favored by it.

It would have been great if, during the planning stage of the connector road, plans had been incorporated to put up a bus rapid transport system (BRT) from end to end of the Skyway -- from Balintawak in the north all the way down to Alabang in the south, with identified stops to maximize the flow of people in the system.

At the street level, a lot of road construction and extensions has been done, but we cannot use the roads fully because many are used as parking for both private and public vehicles as well as for business (e.g., street hawkers selling various merchandise, vulcanizing shops, and flea markets, among others). Pedestrians are thus forced to walk on the streets, impeding traffic flow. Let us clear all these streets of these impediments.

It is quite a simple solution to also put up public utility vehicle (PUV) loading and unloading stations, a practice in many countries. It just boggles my mind why we cannot implement the same in Metro Manila. PUVs that stop with impunity to load and unload passengers create havoc in the traffic flow.

The last time I checked, tricycles, and pedicabs are not allowed on city streets. But you can find them everywhere! Because they are slow-moving, they also slow down other vehicles. Let us ban them from city streets.

Pedestrians cross everywhere, all the time and at will. They put their lives at risk and affect traffic flow. Let us in earnest identify pedestrian lanes, build overpasses and underpasses, and start fining jaywalkers.

Every now and then, traffic comes to a standstill because of rallies or events that occupy major city streets. Even without these events, traffic is already unbearable. With them, traffic is locked down and vehicle flow restricted. We should not allow any interest group, whether public or private, to occupy streets for any activity. Such a policy is for the greater good.

These are just some things that traffic management people need to consider to solve the traffic gridlock in the city and provide a whiff of relief from the daily grind that commuters experience.

Dennis L. Berino is an Associate Professional Lecturer of the Decision Sciences and Innovation Department of the Ramon V. Del Rosario College of Business of De La Salle University.