ACTAR Vehicle Damage Analysis 3 — Questions and Answers
Question 1: In an underride collision where a car slides under a truck trailer, which vehicle surface typically shows 'contact damage' matching the car's roofline?
- The truck's rear axle housing
- The underside of the truck trailer floor or rear cross-member (Correct answer)
- The truck's fifth-wheel coupling
- The truck's front bumper
Correct answer: The underside of the truck trailer floor or rear cross-member
In a rear underride, the car's upper structure contacts the underside of the trailer, leaving characteristic scrape and crush marks on the trailer floor or cross-member.
Question 2: The 'damage profile' method of matching vehicles in a two-vehicle collision involves:
- Comparing paint color samples from both vehicles
- Verifying that the height, shape, and character of damage on one vehicle corresponds geometrically to the striking surface of the other (Correct answer)
- Measuring the coefficient of friction at the scene
- Comparing the odometer readings of both vehicles
Correct answer: Verifying that the height, shape, and character of damage on one vehicle corresponds geometrically to the striking surface of the other
Damage profile matching confirms a collision pairing by verifying that the geometry, height, and character of damage on Vehicle A corresponds to the contact surface geometry of Vehicle B.
Question 3: A vehicle's unibody structure shows 'diamond deformation' after a collision. This means:
- The roof has been crushed uniformly downward
- The body has been distorted so the passenger compartment is skewed into a parallelogram shape (Correct answer)
- The front bumper has separated from the vehicle
- The wheel wells have been pushed inward symmetrically
Correct answer: The body has been distorted so the passenger compartment is skewed into a parallelogram shape
Diamond deformation occurs when one side of the vehicle is pushed rearward relative to the other, distorting the body into a parallelogram or diamond shape when viewed from above.
Question 4: Which type of damage pattern is most indicative of a vehicle rolling over during a collision?
- Concentrated frontal crush limited to the bumper zone
- Distributed damage on the roof, A-pillars, and door sills consistent with ground contact (Correct answer)
- Deep lateral intrusion confined to one door
- Rear-end crush with intact roof structure
Correct answer: Distributed damage on the roof, A-pillars, and door sills consistent with ground contact
Rollover events produce characteristic damage on the roof and pillars from ground contact, along with scraping and crush marks on the sides and roof panels.
Question 5: When using photogrammetry to document vehicle crush, the primary advantage over manual tape measurement is:
- Photogrammetry is always faster in the field than tape measurement
- It allows three-dimensional documentation and measurement from images after the vehicle has been repaired or scrapped (Correct answer)
- It eliminates the need for any calibration targets
- It requires no specialized software or training
Correct answer: It allows three-dimensional documentation and measurement from images after the vehicle has been repaired or scrapped
Photogrammetry enables accurate 3D measurements to be extracted from photographs after the fact, which is critical when vehicles are repaired or destroyed before a full investigation occurs.
Question 6: In the context of ACTAR vehicle damage analysis, 'contact damage' is best distinguished from 'induced damage' by:
- Contact damage is always more severe than induced damage
- Contact damage occurs at the point of force application, while induced damage occurs away from the contact zone (Correct answer)
- Induced damage is always limited to the vehicle interior
- Contact damage only occurs in head-on collisions
Correct answer: Contact damage occurs at the point of force application, while induced damage occurs away from the contact zone
Contact damage is located directly where the impact force was applied, while induced damage appears elsewhere in the structure as a result of load transmission.
Question 7: A vehicle's bumper system is designed to absorb energy in low-speed impacts primarily through:
- Permanent plastic deformation of the bumper face bar only
- Compression of energy-absorbing foam or crush cans behind the bumper face bar (Correct answer)
- Deflection of the vehicle frame rails
- Activation of the vehicle's supplemental restraint system
Correct answer: Compression of energy-absorbing foam or crush cans behind the bumper face bar
Modern bumper systems use foam absorbers or collapsible crush cans between the face bar and the vehicle structure to absorb kinetic energy in low-speed impacts without frame damage.
ACTAR Vehicle Damage Analysis 3
In an underride collision where a car slides under a truck trailer, which vehicle surface typically shows 'contact damage' matching the car's roofline?