What is the primary danger of driving too closely behind a large freight truck (pesado de mercadorias)?

1. The truck severely blocks forward forward visibility, and the following driver enters the truck's rear blind spot (ângulo morto)
2. The truck's exhaust will instantly stall the following vehicle's engine
3. The truck will cause the following vehicle's headlights to overheat
4. The following car's speedometer will register inaccurate readings