I have lived in one of those SE Asian countries in my previous life and now I think it's a jungle rule there in transportation.
Here are two I dealt with closely.
One of my friends' brother/wife/kid were riding a motorcycle.
A local passenger bus hit them and they were knocked down on the road.
It wasn't high speed as the buses travel very sluggish in heavy traffic areas.
The bus backed up and ran over them. Kid survived as another pedestrian picked the kid before bus could run over.
Another incident, two college students riding a motorbike hit a stopped bus that was loading passengers.
The passenger of the bike fell down, not hurt and was trying to stand up but the bus backed on him and killed him. The biker (driver) ran out of the way before bus could run him over as well. College students closed the city for few days in protest but dead is dead.
In both incidents like thousands others, driver fled the scene leaving the bus there.
In few incidents, angry people burn the bus but it doesn't even belong to the driver.
Yes, it'd be murder here but here's how it works there.
Public bus/trucks/taxis etc... have union.
They all pay the union monthly fee.
When an accident like that happens, there are two levels of compensation:
Death: Around $500 to $2000 USD (was even less before) per person.
Injured: Need to pay for treatment.
Since union pays for the dead, drivers prefer the victims to die rather than injured as treatment may take months/years and driver personally has to keep on paying certain portion to the union or to the victims.
Private drivers go by law.
Even if someone deliberately hits someone, it's still an accident.
Compensation for dead or treat injured.
Since auto insurance is still non-existent, it's all from their personal bank accounts.
So when you are in SE Asian countries and got hit, it's in your best interest to get up and run away or at least get up to the curb or something.
It's whole another world there, I guess that's why it's called third world.