Motor Vehicle Accidents FORENSIC PATHOLOGY Motor Vehicle Accidents

MOTOR VEHICLE ACCIDENTS Why perform an autopsy after a MVA? Determine cause of death Confirm death was caused by injury in the MVA Determine extent of injuries Detect any disease or factor which may contribute to MVA Document findings for criminal or civil case Establish positive ID of body

MOTOR VEHICLE ACCIDENTS Causes of MVA Impairment of driver is most common 50% of all crashes are due to DUI of alcohol or drugs Drugs may be prescription Even marijuana impairs driving skills 2nd cause is human error Speed, reckless driving, falling asleep at wheel 3rd cause is environmental hazards

MOTOR VEHICLE ACCIDENTS Four Major Categories of MVA’s in descending order of fatality for automobiles Front impact Side impact Rollovers Rear impact

MOTOR VEHICLE ACCIDENTS Four major categories of MVA’s for pickups and utility vehicles in descending order of fatalities Rollovers Frontal impact Side impact Rear impact

MOTOR VEHICLE ACCIDENTS Front Impact Crashes In a head on collision if the driver is not restrained the body will continue its frontal movement Strike instrument panel at knees Strike chest on steering wheel Strike head on windshield of visor

MOTOR VEHICLE ACCIDENTS Front Impact Crashes Knees May have patterned abrasions Fractures of the patella Fractures of the femur or hip joint Especially neck of femur Exsanguination may occur

MOTOR VEHICLE ACCIDENTS Front Impact Crashes Chest May impact steering wheel or dashboard Imprinted abrasions/contusions Internal injuries Fracture of sternum and/or ribs Lacerations, contusions, rupture, transection of vital organs Liver, spleen, heart, aorta

MOTOR VEHICLE ACCIDENTS Front Impact Crashes Head Patterned abrasions Impact windshield Windshield does not shatter Thin outer and inner layers of glass, thick core of plastic Dicing injuries Avulsion of skin especially to head Basilar fractures of skull Hinge fractures Fractures of neck Atlanto-occipital junction dislocation

MOTOR VEHICLE ACCIDENTS

MOTOR VEHICLE ACCIDENTS Unrestrained injuries usually occur in sequence Knee-femur-hip-chest-head Restrained injuries are dependent on the force of the crash

MOTOR VEHICLE ACCIDENTS

MOTOR VEHICLE ACCIDENTS Side Impact Crashes Broadside at intersections most common Driver’s side Head can flex laterally through side window Head may hit pillar of car Injuries are typically worse on left side of body Head may pop out of window and pop back into vehicle Head may hit objects before re-entering vehicle

MOTOR VEHICLE ACCIDENTS Rollovers Generally less lethal than head-on and side impact collisions If not wearing seatbelt may be thrown around like a rag doll in compartment Receive multiple injuries Body may also pop out of vehicle and pop back in again Check for paint on head or hair on vehicle

MOTOR VEHICLE ACCIDENTS Rollovers Most rollovers occur because driver runs off the road and attempts to steer back onto road Vehicle skids sideways Vehicle tips towards leading side Where rollover begins is where tire marks stop Center of gravity determines extent of rollover SUV’s rollover more

MOTOR VEHICLE ACCIDENTS Rollovers Vehicles that roll over go airborne Cars land on edge of roof opposite side that led in rollover SUV’s impact on leading edge of vehicle roof then onto tires Most vehicles only roll over once

MOTOR VEHICLE ACCIDENTS Rear Impact Crashes Least common of fatal accidents Mainly see whiplash syndrome May have fire due to faulty gas tank May have seatback failure

MOTOR VEHICLE ACCIDENTS

MOTOR VEHICLE ACCIDENTS Seat belts Lap belts Shoulder belts Three-point belts Lap plus shoulder

MOTOR VEHICLE ACCIDENTS Seat belts All new vehicles have three-point belts Since 1997, 69% decrease in MVA fatalities due to seat belt law Jack-knifing may occur with lap belts Seat belt syndrome

MOTOR VEHICLE ACCIDENTS Air bags Significantly less effective than seat belts Only improves your chance of survival by a maximum of 5% May produce injuries especially in children and small adults Less than 10 inches from bag

MOTOR VEHICLE ACCIDENTS Motorcycle Accidents Fatalities are due mostly to head or neck injuries Many abrasions High speed crashes wearing helmets are only to keep brain matter from spreading over the freeway

MOTOR VEHICLE ACCIDENTS Motorcycles Most fatalities are due to Car drivers don’t see the motorcycle Environmental factors Wires or cables stretched across roadway Avulsed limbs Decapitation

MOTOR VEHICLE ACCIDENTS Suicide by Motor Vehicle Usually head on into a fixed object Check soles of shoes of driver for pedal marks May also do this to determine who was driving in a crash

MOTOR VEHICLE ACCIDENTS Toxicology and MVA’s A complete toxicological screen should be done Include Carbon Monoxide levels In 1999, 38% of traffic fatalities were alcohol related down from 49% in 1989 Should also drug test passenger Passenger often turns out to be driver Blood may be kept at a hospital for up to 7 days

MOTOR VEHICLE ACCIDENTS Pedestrian Deaths by MVA’s due to four factors Speed of vehicle Physical characteristics Braking of vehicle Whether victim was a child or an adult

MOTOR VEHICLE ACCIDENTS Pedestrian Death – Speed of Vehicle Fracture of spine, 45 km/h Rupture of thoracic aorta, 85 km/h Inguinal skin rupture, 95 km/h Dismemberment, above 95 km/h

MOTOR VEHICLE ACCIDENTS SUV’s Child Pedestrians Body’s center of gravity is below bumper For non-braking or late braking vehicle: Victim will be impacted, slammed down and run over For braking vehicle: Front of vehicle dips below child’s center of gravity and child may be thrown forward

MOTOR VEHICLE ACCIDENTS Adult Pedestrians Body’s center of gravity is above bumper, except for tall vehicles, i.e. pick-up or SUV Trucks or SUV’s Non-braking: Victim is slammed down and run-over Braking: Victim is thrown forward

MOTOR VEHICLE ACCIDENTS Adult Pedestrians Automobiles or light trucks Non-braking or late braking at high speeds: Victim is picked up and thrown over top of car Look for scuff marks or dents on bumper, hood, roof and possible trunk of vehicle Non-braking at moderate speeds: Victim will be picked up, land on the hood and slide backward impacting windshield, then slide off (usually sideways) Look for scuff marks or dents on bumper, indent on hood and impact to windshield Glass may be in hair of victim May find hair or clothing in cracks in paint or in glass on vehicle

MOTOR VEHICLE ACCIDENTS Automobile or Light trucks Braking at high speeds: Victim may be thrown forward or may be picked up and land on the hood and then propelled forward again Look at knees and calf region for fractures “Bumper Fractures” If walking or standing sideways may be fractures at different levels or fracture in only one leg

MOTOR VEHICLE ACCIDENTS Automobile or light truck Individuals picked up and thrown by a vehicle may be stripped of clothing If Victim is run over by a wheel Look for tire marks and abrasions on opposite side of body

MOTOR VEHICLE ACCIDENTS Future of MVA’s Black Boxes Already in Mercedes and All GMAC models

MVA

MVA

MVA

MVA

MVA