Myanmar traffic doesn't compare to Vietnam. Everything moves slower and there is exponentially less vehicles on the streets. The one big difference though between Vietnam and Myanmar is that there are almost no motorbikes in Myanmar cities. The roads are basically filled with bicycles, old old old cars and pick up trucks that serve as buses.
From what I'm told, Myanmar's inner city traffic is a lot like Hanoi was seven or eight years ago. There are very few traffic lights in the city and the roads often have huge potholes. I recorded a minute or so of some typical traffic: