This is going to be an ongoing topic and as such, so will this article be. I’ll post on Twitter when I update it. Let me just now make some initial observations after having been in the country only about twenty-four hours now.

As Jeremy Clarkson once said about traffic laws in Italy, they’re more suggestions and less rules.  Same in Colombia.  A red light probably means “stop”.
Lines on the road are, again, merely suggestions.  Roads with only two official lanes are frequently made to fit three lanes worth of traffic.
People just shove in everywhere but no one seems to mind.  Seems like as long as you don’t hit anyone it’s fine.  It’s a bit chaotic but it seems to work, and it works only because everyone is on the same page: they’re all playing by the same rules (this is an important theme in anthropology you’ll notice keeps popping up time and time again).  There’s a mutual understanding that it’s ok to do these things as well as how to react when those things are done to you.
Oddly enough, all of the motorcyclists and many of the bicyclists wear helmets.

Pedestrians vs vehicles

Vehicles have right of way.  Motorcycles will generally go around you but cars, trucks, and buses all expect you to get out of the way, they don’t expect to have brake for you.  You really have to pay attention when you’re crossing roads here.
That’s all for now, I’ll update when I have more.  I recorded about 20 minutes worth of video footage while being driven from my hotel to my apartment that’ll help support my claims and which you may find interesting, but I still need to edit it.  For now I’m tired and going to bed.