Understanding the term “person-trip”

Published in The Freeman (Philippine Star), Feb. 23, 2012

In previous articles, we wrote about land use and transportation. Land use is the main contributor to transport – the kind of use, and their arrangement on the map, governs the transportation system which is needed and how this shall be arranged. It follows that how we managed the two sectors will determine whether we have a nice and easy travel experience or we will have a monstrous daily traffic jam.

The contribution of land use to the design of a transportation is mainly on the population and how they move daily. The foremost land use is residential – we have to recognize that no matter what we do, about half of the 24 hours we have are spent at home with our families, and much of it sleeping in our beds. The rest of the time are the ones devotes to work, school, doing business, social and recreational functions, and other activities. The times we are not at home also includes the time we need to travel – the time we spend transferring from one place of activity to another.

Transportation is important not only because we need to transfer but because we need to transfer fast, because travelling is the only activity which is not productive, unless you’re a driver or a conductor. That’s why we always refer to time wasted in traffic jams. If it takes you 2 hours to commute between home and work each day, it is 2 hours relatively wasted. That two hours spend on the streets is valuable, not only to you but to the country as well, because productive time wasted is an opportunity loss in our gross national product (GNP). By this time, you may have realized why this column is called “Streetlife” – the matters we discuss here concerns life when we are on the street, that which we always dismiss as unimportant.

But in planning for a better transport, what do we use as the basic unit of measurement? We use the not-so-familiar term “person-trip.” The dictionary defines a person-trip as “a trip by one person in any mode of transportation. If more than one person is on the trip, each person is considered as making one person-trip. For example, four persons traveling together in one car account for four person trips. If you use another mode of transport, that’s another one person-trip. Suppose in your way to work in the morning, you start by walking to the corner, taking a trisikad to the main road, riding on a jeepney, then riding a tricycle to your office, that’s four (4) person-trips. If you return home the same way, that’s 8 person-trips you contribute to the city’s transport needs in a day. It is assumed that you didn’t pass by anywhere else – mall, church, restaurant, bar, on your way back, else that’s an added person-trip. Note that “walking” is considered a transport mode! This is important once we discuss “walkable cities” at a later time. If you instead use your personal car, that’s a door-to-door service, and you contribute only 2 person-trips each day.

Let’s classify person-trips, then. There are really no strict categories. As to the purpose of the trip, we may classify them into four: home-to-work, school or church, personal/family matters, or social/recreational. As to mode, what’s commonly existing in the Philippines are walking, habal-habal, trisikad, tricycle, multicab/FX/megataxi, jeepney, V-hires/GTs, minibus, bus, LRT/MRT, taxis and private cars. The total number of person-trips made by the people in a particular city, is what we call the transport demand. If we segregate the person-trips by mode made by the same population, that’s how our transport infrastructure services looks like. What is significant here is that each mode has different capacities – a private car/taxi can normally carry up to 4, a bus maybe 80. How we configure supply and demand determines whether we have a good or bad transportation system. (to be continued)

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