7a Road Traffic Collisions

Question 1

The phrase ‘road traffic ______’ tends to be used nowadays in medico-legal work rather than ‘road traffic ________’

Answer 1

The phrase ‘road traffic COLLISION’ tends to be used nowadays in medico-legal work rather than ‘road traffic ACCIDENT’

as not all ‘accidents’ are necessarily that

Question 2

In a road traffic accident, what determines the outcome for a victim? (vehicle occupants) (8)

Answer 2

For vehicle occupants:
1. speed of impact
2. direction of impact (.e. frontal/side
3. position in the car (i.e. driver/front passenger/rear passenger)
4. use of seat belts
5. degree of intrusion i-e- parts pushed in
6. if the vehicle rolls over or is crushed
7. any subsequent fire

Question 3

In a road traffic accident, what determines the outcome for a victim? (pedestrians) (3)

Answer 3

1. speed of impact
2. nature of the vehicle
3. any subsequent run-over

Question 4

Should we comment on injuries from speed seen?

Answer 4

Apart from general comments, be very cautious in commenting on speed from injuries seen if you are ever asked to do so

Question 5

Mechanism of injury for vehicle occupants (driver)

Answer 5

Driver: is thrown forwards and upwards and suffers:
- head injury from striking the windscreen or corner pillar
–chest injury from impact with the steering wheel
- leg injury from striking the structures below the steering wheel

Question 6

mechanism of injury of front passanger

Answer 6

front passenger is thrown forwards and upwards and suffers:
- head injury from striking the windscreen or conrer pillar
- leg injury from striking the internal structures at the front

Question 7

Mechanism of injury rear passenger

Answer 7

is thwon against the seats in front and suffers:
- head, chest and abdominal injuries

Question 8

Typical external injuries in car occupants

Answer 8

abrrasions, bruises lacerations
- specific patterns, e.g. from window glass, from seat belt

Question 9

typical internal injuries in car occupants

Answer 9

fractures, tissue damage, hemorrhage (e.g. skull fracture, brain injury, pulmonary contusion, ruptured aorta)

Question 10

besides typical external and internal injuries in car occupants, what are some other things that can kill you as an occupant? (2)

Answer 10

• crush asphyxia (from being trapped under the vehicle if it has overturned)
• burning (from the car going up in flames while trapped inside)

Question 11

Mechanism of injury for pedestrians

Answer 11

in a standard case, i.e. a car striking a pedestrian in front, there is a sequence of events :

1. primary impact:
   the person is initially struck by the bumper or the edge of the bonnet (results in injuries to the legs)
2. secondary impact: the person is thrown up onto bonnet and striked his or her head on the windscreen or surrounds (head an chest injuries - skull fractures, brain injury, rib fracture, pulmonary contusion)
3. tertiary impact: a car brakes, the person is thrown forwards onto the road producing broad surface injuries (brush abrasions, lacerations), possible (further) injuries to the head and to other parts

Question 12

Mechanism of injury of a pedestrian varies from… (3)

Answer 12

varies if
1. struck by a flat fronted vehicle
2. struck by a very fast vehicle
3. run over while on the ground

Question 13

measures for driving safely

Answer 13

1. seat belts - reduces the risk of death by 65% and offers much greater protection than air bags (only 8% protection)
2. tiredness: driving while feeling sleepy, after less than 5 hours of sleep or between 2 and 5 am is associated with a substantial increase in the risk of a crash resulting in serious injury or death
3. 4 wheel drive vehicles : pedestrians are 2x llikely to die if struck by a 4 wheel drive vehicle than an ordinary car and children are not seen well