Induced demand or traffic is a popular topic these days thanks to the proposal of a private company to build an elevated tollway along the Pasig River. The topic is also much in circulation the past few years as the DPWH’s part in the government’s Build, Build, Build program has road widening as a major component. There are many completed, ongoing and planned projects across the country that involves road widening, particularly increasing the number of lanes of typical national roads from 2 to 4, not counting the shoulders (paved or unpaved). The results are mixed as there are roads that definitely required capacity increase in the form of additional lanes, and there were roads that did not require them. The latter were still expanded and perhaps the agency did so because their key performance indicators basically obliged them to undertake such projects regardless of the need. Somehow, these were justified and yet there were and are many questionable road widening projects especially those that involved the cutting of decades if not century old trees (e.g., the Kamatchile and Acacia trees that used to line up long sections of national roads in Tarlac are no more) or the demolition of heritage structures such as houses.
A came upon this article about an “Induced Demand Calculator” developed in the US. I have not gone through the calculator itself but such a tool could be quite useful in quantifying the impacts of road widening while pushing for other options to improve transportation and traffic that is not the typical “solving traffic” type of approach. Here is the article in Streets Blog:
I am not aware if there are similar tools being developed here. Such a calculator will require data from various sectors including construction costs, operations and maintenance costs, value of time and current and projected vehicular and person trips that can be translated into traffic volumes.