I second IWAF remarks.

Once I spoke to my brother who is a 'bendy bus' driver about the incidents where a bus had dragged a person for a considerable distance before the driver noticed it had run over a person. My brother's response was that so many tonnes of a bus verses 80 kg person, the bump would not be anything distinguishable from the normal drive. I was completely astonished to hear that as you would compare such an incident with car driving and assume the driver must have known of the damage they had caused.

It had opened my eyes and gave me a greater respect for all the drivers of heavy goods vehicles.