Buses and trucks are involved in a disproportionate share of serious motorbike accidents in Vietnam — not because their drivers are malicious, but because a motorbike hides perfectly in their blind zones. Knowing where those zones are is basic survival knowledge here.
The map
A bus has blind zones directly in front (behind the windscreen pillar area), tight alongside both doors, immediately behind, and a large wedge behind the driver on the left. A truck adds a deep blind wedge down its right side. The rule of thumb: if you cannot see the driver’s face in their mirror, they cannot see you.
Do not live there
Blind zones are for passing through, not travelling in. Alongside a bus, either hang back or clear the zone quickly at a steady speed — do not cruise next to the rear axle for a kilometre. At stops, expect buses to pull out toward the curb lane: Hanoi buses re-enter traffic boldly, and a bike squeezed between the bus and the curb has nowhere to go.
Passing
Pass decisively and on the correct side — the legal overtaking rules are in overtaking-rules-motorbike-vietnam. Before moving out, check your own mirror: another bike is usually about to pass you. Never cut back in front of a heavy vehicle; its stopping distance is far longer than a car’s, and the driver may not even know you are there.
The turning truck
The deadliest blind-spot scenario is a heavy vehicle turning across your path. If a bus or truck ahead signals, slows or drifts near a junction, assume it will turn across you and drop back — defensive-riding-motorbike-vietnam covers the general mindset.
The one-line version
If you cannot see the driver’s face, they cannot see you — pass blind zones quickly, never cruise inside one, and never cut in front of a bus.