How to drive in Sri Lanka

After almost 3 weeks in Sri Lanka, the local driving habits still give me the willies.
We started off our holiday with a few days in the bustling hectic capital city, Colombo, which, as regards coping with traffic, was something of a baptism of fire. Cars, buses, trucks, motorbikes and the ubiquitous little three-wheeled tuk-tuks, even the occasional horse-and-cart, all vie for dominance in the cut-throat game of chicken that is Colombo traffic. Road markings, where they can be made out, are moot, pedestrian crossings likewise, and many of the traffic lights are not actually working. Vehicles of all kinds nip into any available space, as though to fill a vacuum, and the air resounds with the sounds of horns of various tones and tunes, creating a constant barrage of ambient noise.
At first, we were very tentative pedestrians, scuttling across roads in the shadows of other, more confident, local pedestrians. But, after a while, we realized that, in Colombo at least, fortune favours the brave, and, if you walk out with enough chutzpah, cars and even tuk-tuks will in fact stop to let you cross (buses less so, and you do risk life and limb walking out in front of one).
It was quite noticeable that the various taxi and tuk-tuk drivers we used were remarkably calm and unperturbed by all the chaos around them, and remained zen-like even when cut up unashamedly by a tuk-tuk driver on a mission. All the hooting and horn-blaring is not in anger, but merely to say, "Look out, I'm coming through" or simply, "I am here", or sometimes just, "Hello". The driving appeared aggressive to us, and it is certainly a dog-eat-dog road culture where giving any quarter is clearly seen as mere weakness to. But everyone seems hyper-aware of the vehicles around them, and, improbably enough, I don't think we actually witnessed a single accident the whole time we were in Sri Lanka.
In more rural areas, the traffic moves faster, and appears to the outside eye to be equally aggressive and chaotic. Here the buses, both government and private, rule the roads, and you don't mess with them. Overtaking on blind corners is perfectly normal, and other vehicles just lurch onto the shoulder or grass verge if necessary, with nary a backward look or a bad word. On the many miles of steep, winding, often single-track, roads we traversed, passing (both oncoming and same direction traffic) is achieved by whatever means necessary, and somehow, miraculously, it all seems to work. Wild animals and, particularly, the massive population of stray and feral dogs present added obstacles on rural roads, and drivers have to be constantly on guard for the occasional elephant, water buffalo, wild boar or monitor lizard to amble across the road around any corner. Whole herds of lazy cows wander around on the roads, with no apparent human supervision.
But it was the dogs that really stressed me out. There are thousands of them, mainly around villages, but sometime out in the middle of nowhere. The early mornings are particularly tricky, as most dogs seem to acually sleep on the roads, and only grudgingly move for traffic, if at all. Some dogs appear to be able to continue sleeping while traffic whizzes past within centimetres of them. "Let sleeping dogs lie" seems to be the watchword, and Si Lankans deal with them with great sang-froid.
One particularly bizarre part of the road network is around Hambantota, on the south coast, which is where the current (outgoing) president hails from. He has authorized a huge network of brand new, beautiful, four-lane highways around the town (finished just in time for the November elections) even though the roads see very little traffic. It feels almost spooky to drive over a large clover-leaf intersection - top-notch engineering worthy of North America or Europe - with hardly any vehicles to be seen. The locals, though, particularly motorbikes and tuk-tuks, have already learned to improvise, and now drive both ways down both carriageways. Sri Lankan traffic drives to its own rules.