Building transport capacity - PPHPD
Our article two weeks ago had a heading "Building Transport Capacity - but for whom?" Maybe I should asked, "for what or which, since 'whom' suggests persons;" but it might be correct, too, since society is so diverse, we really need to ask for whose benefit we build transport infrastructure for. But let us be very clear from the start - the traditional concept of building transport capacity was always in relation to cars, not people. And that hasn't changed till now.
You read through any feasibility study on road-building or widening and the numbers would always be vehicles. Of course, these come in many sizes so transport engineers need to bring this down to the lowest denominator, and since the most popular, and the most important to a lot of people are their cars, we measure traffic demand, and capacity in "passenger car units" or PCUs. Traffic counts classify vehicles into private cars, motorcycles, vans, trucks, buses, etc. but in order to come up with comparative values, the different vehicles are multiplied by a factor to reduce them to PCU. Private cars, of course, have a factor of 1, maybe 1.5 for a van, 2 or 3 for a minibus or bus, etc., depending on which jurisdiction. Then you total them in PCUs.
Traditional traffic planning simply measures road capacity in PCU, determine the present demand, multiply an annual increase (called annual average daily traffic, or AADT), then compute future traffic 30 years from now. Then you design the road capacity 30 years from now. This is the traditional thinking and this is what almost everybody thinks today. If you go through all the discussions in the social media and even in the local news, people are demanding for solutions because "the roads cannot accommodate the number of cars!"
I am even willing to suggest you wouldn't find a single statement in the news or social media, which suggests that our transport system cannot move "PEOPLE" to their daily destination. We go back to "people" versus "cars." A few people will say we plan for people and not cars, but on the same breath say this type of transport is better because "it's the best in the world," and "most modern countries/cities have them" without mentioning their capacities. But at the end of the day, the effectivity of a transport system depends not on the number of cars it carries but its ability to move people to their destination the least possible time. Unless you're sight-seeing!
We need to go to the METRIC used. And the most appropriate, although the least known or talked about is PPHPD - persons per hour per direction. Suppose you have 40,000 people to be transported from Talisay City to LapuLapu City in two hours, how do we do it? We can build a road system and transport everybody by cars, one each; use carpool (4 each), jeepney, tricycle, multicabs, LRT, BRT, subway (metro), cable car, monorail, or walk/run (maybe not). The question is, what are the respective capacities of each in PPHPD? It's a no brainer to conclude that the best system would be the most number of persons in the least time.
Of course, after that, we apply the cost criteria. A system may have a 10% higher PPHPD capacity than another but if it costs 10 times as much, it would be ridiculous to insist on it. In NEDA lingo, you determine the best effective transport capacity, then you determine the economic viability. Mind you, the main decision factor will always be the Economic Internal Rate of Return (EIRR), whether you're in NEDA or the World Bank, or any international financing institution of Official Development Assistance (ODA) agency.
PPHPD is what determines what the better transport system is or should be. EIRR will provide you the decision criteria. Let's try to look closer at PPHPD in our next article.