Those famous, or notorious, U-turn slots

Time is distance and distance is time, right?  The phrase “a stone throw away” is already an old cliché - no one seems to be in a habit of throwing stones, nowadays.  But “five minutes to the mall,” or “an hour’s drive to the airport” is already an acceptable, even preferred, measure of distance.  What escapes majority of the population is that there is still a correlation between distance and time, and that people behave according to perception rather than to real facts about distance and time in travel.  This is most evident in Manila’s U-turn slots.

There was a time a when a certain hero-chairman of MMDA introduced the concept of U-turns in Manila’s otherwise unsolvable traffic congestion.  They closed certain intersections, preventing thru- and left-turning traffic and forcing everyone to turn right … for those who would have wanted to pass through or turn left, you turn right and then make a U-turn farther down the road.  The U-turn slot causes continuous flowing traffic, albeit slow at times, in contrast to the stop-and-go movements introduced in a signalized intersection.

Voila! Flowing traffic you have alright.  The MMDA hero constructed hundreds of U-turn slots in Metro Manila.  A lot of people in the capital praised the move, a similar number criticized him.  A matter of perspectives.  But what is the real score?  Let’s introduce the concept of perception…. Sometimes, or in fact oftentimes, we are fooled to believe one thing because of the way we perceive it, not on what they really are.  The question we have to ask is, “Did travel time really decrease?”  Or, and here comes the perception part, “Did people think they move faster because they were constantly moving instead of waiting for the signal to turn green?”

The real determinant is measuring the time from point A to point B.  People in general, but especially drivers, prefer that their cars are moving instead of waiting for the a “go” signal, which, in a 6 x 6, or 8 x 8 intersection, may seem forever.  This is the merit of the U-turn slot – they allow slow continuous movement, over a much longer distance, instead of the stop-and-go of an intersection.  In reality, there lies the possibility that it actually takes longer for you to get to your destination.  The results of a recent modelling study revealed that in fact, the traffic efficiency of U-turn slots is dependent on the congestion level of the intersection itself, and that it is only good if the intersection is below a certain level.  On higher congestion levels, U-turn slots actually slow down traffic and adds more to the congestion!  On majority of Metro Manila’s thoroughfares, this certainly is the case.  In other words, they’re not working.

That’s just a case in point.  But it is equally true for the rest of the transportation sector.  This is true because transport performance has a direct relation to economic growth.  The economy is fuelled not only by production, but also by how products, and the people who produced them, are transported from one place to another.  Travel time has an economic cost for both people and goods and services.  The less economic goods (this includes people) stay on road, the better for the economy.  So we should not introduce transport infrastructure which makes people think they’re in better traffic when in fact they are not.

But the even worse notion is introducing road infrastructure which allows people to live farther and farther away from their places of work.  It may seem like a nice idea at first, many people in Manila readily fell for this, relocating hundreds of kilometers away where land is cheap.  Now they’re paying heavily on transport costs.  Ask any of your acquaintances in the capital.  The key to this is travel time vis-a-vis trip length, which is our topic for next week.

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