For Vietnamese people they get used to crossing busy traffic streets but for foreign tourists you should know how to do.

It is the best advice that you you cross the street at the intersection when the traffic light turns green. You can follow the locals when they do cross the street, Vietnamese people are friendly. Make a sign by putting your arm in the air to make you more visible to the traffic. 

If you cross the street outside the intersection you pay attention to left and right side first till feel safe then should walk ahead slowly but steady, not turn back, then the traffic flow will move around you. 

Don't be worry or afraid when crossing street in Vietnam. You will be familiar to it quickly. Happy traveling in our beautiful country.