I learnt alot about crossing roads in Vietnam amidst the seemingly chaotic & frightening number of motorcycles on the road.
Lesson 1: Hang on to your belongings. Best not to carry any bags and keep all your valuables in your pockets.
Lesson 2: No cha cha. Don't do the one step forward two steps back manoeuvre as the motorcyclists usually zip pass a pedestrain from behind.
Lesson 3: No cars or motorcyclists will stop for you, even at zebra crossing. You have to take the inititative the motorcyclists will avoid you.Lesson 4: Walk quickly but don't run.
Ratio of cars to motorcycles? My guess? At least 1 to 20.