Road Traffic Collision Investigation Flashcards
Car Safety Features
Front airbag crush sensors
Load limiting suspension cradle
Tyre pressure monitoring
Energy absorbing steering column
Body structure crush beads and stiffeners
Multi-stage air bags
Inflatable knee blocker
Three point lap shoulder belts
Seat belt sensors
Seat belt pretensioners, constant force retractors
Side curtain air bags
Side impact airbag sensors
Child seat anchor system
All wheel drive
High-speed rear impact protection
Causes of Vehicle Accidents
Environmental conditions
- Weather conditions
- Sun glare
Human error
- DUI of drugs/alcohol
-Illness, fatigue
-Distraction
-Use of mobile phone
Vehicle malfunction
-Poor maintenance
-Brake failure
-Poor tyre condition
Accident Vocabulary
Reconstruction - Recreating actions and circumstances based on the examination and interpretation of the evidence
Contact Damage - Damage done to a vehicle caused as a result of contact with an object or another vehicle
Skid Marks - Marks left on the roadway by tyres when the driver of the vehicle applies the brakes suddenly
Staging - Intentional altering of a crime scene in order to disguise what really happened
Yaw marks - tyre marks in a curved path as a result of an out-of-control skid
Collision Investigator Role
Identify extent of scene
Capture all available evidence
Interpret scene evidence
Carry out any ‘testing’
Examine vehicles
Driver related ‘issues’
Review evidence
Compile report
Investigators include
- Mechanical engineering background
- Police officers
- Vehicle mechanics
- Private companies
Stages of Investigation
- Collision Occurs
- Investigation commences
a. Recording phase
i. Level 1 - Collection of basic information
b. Investigative phase
i. Level 2 - Scene
ii. Level 3 - Technical Follow-Up
c. Reconstruction
i. Level 4 - Reconstruction
ii. Level 5 - Cause Analysis - Information is gathered
a. Investigation Reports Findings
Explain step 2
Investigation commences
- Cause
Speed of vehicles
Relative positions of vehicles
Adherence of drivers to road signs
Is the driver under the influence of drugs/alcohol?
- Accident Factors
Position of vehicles involved
Point where a pedestrian may have entered driver’s path
Point of impact
Skid mark location
Damage to vehicles
Damage to roadside furniture
Obstructions and distractions
Safety systems deployed
Road defects
Weather conditions
- Analytical tools
Law of conservation of energy
Law of conservation of momentum
Forensic engineering
- Mathematics
-Physics
Physical evidence
Eyewitness accounts
-Collision Scene Evidence
Tyre and skid mark lengths
Accident area plan
Final vehicle positions
Initial travel directions
Point of impact
Location and depth of impact damage
Impact debris
Vehicle-Vehicle contact marks
Vehicle -object contact marks
Physical and mental condition of driver
Explain Step 2 Level 1
Collection of basic information
- Accident scene-incident management
- Scene protection
- Medical response
- Commencement of recording phase
- Information gathering - reporting
- Training - basic to intermediate level
- Collecting facts not opinions
Police Report
- Diagram of vehicle positions post-accident
- Diagram of
tyre marks
impact marks
impact debris
- Witness statements
- Photographs
Step 2 Level 2
At the scene investigation
- Preservation of evidence
- Determination of causative factors
- Photographic evidence
- Basic calculations - determine preliminary speed
- Software to produce scale plans
- Training - intermediate to advanced
- Photographs and measurements
- Vehicle examination
testing performed
Condition of vehicle noted
Damage related to police report
Post incident damage - Doors or roof cut
- tyre fixed or towing
- Parts stolen
- Alcohol involved?
- Contact damage
- Equipment failure
- Occupant restraints
- Maintenance of tyres, air pressure, headlights, tail-lights
Explain Step 2 Level 3
Technical Follow up
- When crime has been committed
Prepare a map of the crime site
Interview witnesses
Assess visibility at the site
Evaluate evidence
Toxicology Report
Post Mortem report when theres a fatality
Explain step 2 Level 4
Reconstruction
The process of reproducing the actions and circumstances of an accident based on examination and interpretation of evidence
Evidence is used to
- establish a timeline of events and relationships
Outlines accident scenario chronologically
Performed in reverse
Reconstruction outlined generally and details added subsequently
Engineering data adds speeds and directions (Newton’s laws)
- connect victims and suspects involved in the crime
Plan drawing
Applied mathematics and laws of physics
Reconstruction reports
Determination of pre-accident factors
Expert testimony
Training - advanced
Speed Assessments
- Speed lost while skidding
- Critical speed cornering
-Equations of motion
-Establish coefficient of friction between tyres and road surface
Skid tests
Range of values
Determining speeds
Skid marks
Impact analysis
Conservation of linear momentum
Time-distance relationship
Vaults and flips
On board computer analysis
Vehicle characteristics/gear position / speedometer reading
Speed: Factors which determine whether a driver will offend
Chance of being caught
Change of being penalised and to what degree
Financial considerations
Social stigma or peer approval to the offending or getting caught
Risk of injury/damage attached to the offence
Gains in time or convenience
Enjoyment derived from offending behaviour
Skid marks
A tyre mark on the road surface produced by a locked (not rotating) tyre
Typically very light at the beginning, getting darker as the skid progresses and coming to an abrupt end
Generally straight, but may have some curvature due to the slope of the road
Laws of friction govern skidding vehicles
Not to be confused with other types of tyre marks: scuffs, scrubs and yaw marks
