They have massive staging areas where the caravans wait, and when the time is right they let one caravan go in one direction, etc.

I have some amazing photos - unfortunately they are slides, not prints - of our vehicle getting stuck against a random military vehicle that was traveling in the other direction outside of a caravan. The photo is of a crowd of us - soldiers and the passengers in my car - pulling/pushing against our respective vehicles in order to get them "unstuck" from one another - with the 18 switchback valley in the background below us.

Scary, wonderful shit for me back then when I was just 18. I'm not sure that I'd do it again now. hehe.

I've always thought this to be the most dangerous road in the world. I once counted 18 switchbacks below me as I looked out over the edge of one guardrail-free, single-vehicle-width cliff. I can't imagine that it has changed much in the 20 years that have passed since I was there, either.

Traffic is a major problem in metro-Manila. Because of this, Commonwealth was turned into a "through-way" --- stop lights were eliminated. Left turns are done at makeshift U-turn points, jerry-rigged with concrete dividers and steel fences. Ugly and self-defeating, perhaps.

Just a few years ago, the QC gov't installed footbridges on Commonwealth, 2 flights up and over all the traffic. But you have to trek down the road a piece to get to one, depending on where you live. And when the summer heat is sweltering, the crossing will get you sweaty and tired. People still try their luck on the ground-level crossing if they feel that it's a bridge, uh, too far.

Speaking of using mass transit: There are no sidewalks on Commonwealth in some areas. Groups of people will congregate here and there at edge of the driving surface, trying to flag down a taxi (usually a Sentra or a Corolla, but also some mini-van sized vehicles). There have been some occurrences of vehicle-versus-pedestrian fatalities, more often at dusk. One newspaper reported a bystander describing the victims as "going down like bowling pins."

Green note: medians in other areas of QC had trees, planted during a "green" fad. When the QC gov't decided that more lanes were better than more trees, they reversed their effort and removed the medians, along with the trees. I believe that the traffic problem persisted, but without the trees and grass in and along the street, a new problem cropped up: dust. Take a walk down Commonwealth or Katipunan Ave, then wipe a washcloth behind your ears or neck and see that part of the 'street' has collected there.