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Collection of NASS CDS Data Relating to Rollover. Presented to: Committee for the Study of a Motor Vehicle Rollover Rating System May, 29 2001. Robert Woodill – Veridian Engineering John Brophy – NHTSA. NASS CDS Rollover Variables. - PowerPoint PPT Presentation
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Presented to:Presented to:Committee for the Study of a Motor Committee for the Study of a Motor
Vehicle Rollover Rating SystemVehicle Rollover Rating SystemMay, 29 2001May, 29 2001
Collection of NASS CDS Data Relating to Rollover
Robert Woodill – Veridian EngineeringJohn Brophy – NHTSA
NASS CDS Rollover VariablesNASS CDS Rollover Variables
A rollover is defined as any vehicle rotation of 90 degrees or more about any true longitudinal or lateral axis.
The variables also attempt to identify:• What initiated the rollover• At what plane of the vehicle exterior the tripping force was applied and• The direction of the initial roll.
NASS CDS Rollover Variables NASS CDS Rollover Variables (continued)(continued)
CDS Data Collection Screen
NASS CDS Rollover Variables NASS CDS Rollover Variables (continued)(continued)
Rollover Data:•Type•Quarter Turns
Rollover Initiation:•Type•Location•Object Contacted Class•Object Contacted
Rollover Specifics:•Location on Vehicle Where Initial Tripping Force Applied•Direction of Initial Roll
NASS CDS Rollover Variables NASS CDS Rollover Variables (continued)(continued)
Element Attributes:•Trip‑over•Flip‑over•Turn‑over (justify)•Climb‑over•Fall‑over•Bounce‑over
•Collision with
another vehicle•Other rollover initiation type (specify):•Unknown•End-over-end
NASS CDS Rollover Variables NASS CDS Rollover Variables (continued)(continued)
Element Attributes (continued)
•Most Popular One is the:
Cherry Turn-Over:
NASS CDS Rollover Variables NASS CDS Rollover Variables (continued)(continued)
Source for coding rollover variables in CDS NASS:
Researcher determined — primary sources are the scene and vehicle inspections. Secondary sources are photographs, police report, driver interviews, and other interviewees.
Trip-OverTrip-Over
Example 1: Vehicle lateral motion is resisted by opposing force (curb) at wheels, inducing roll moment.
Trip-Over Trip-Over (continued)(continued)
Example 2: Vehicle lateral motion is resisted by opposing force (surface friction)at wheels, inducing roll moment. Tire side wall breaks down and rim gouges usually occur.
RightRight RightRight Rear Rear FrontFront
Trip-Over Trip-Over (continued)(continued)Example 3: Vehicle lateral motion is resisted by opposing force (surface friction)at wheels, inducing roll moment. Wheelsdig into soft soil causing trip.
Trip-Over Trip-Over (continued)(continued)
Example 4: Vehicle lateral motion is resisted by opposing force (surface friction) at wheels, inducing roll moment. Incline helps cause side wall to break down and rim to dig in causing trip.
RightRight RightRight Rear Rear FrontFront
LeftLeft Left Left FrontFront RearRear
GuardrailTaper
Flip-OverFlip-OverExample 1: Forward moving vehicle is vigorously rotated about its longitudinal axis by a ramp like object such as a guard rail taper.
Flip-Over Flip-Over (continued)(continued)
Example 1: Forward moving vehicle is vigorously rotated about its longitudinal axis by a ramp-like object such as a steep embankment.
Turn-OverTurn-Over
Centrifugal forces from a sharply turning or rotating vehicle produce a rollover moment when resisted by surface friction
No Gouges, and NoRight Side Rim Damage
Turn-OverTurn-Over ??
Roof & Left Roof & Left Side Side
DamageDamage
Left Side Wheel DamageLeft Side Wheel Damage
Left Rear Wheel DamageLeft Rear Wheel Damage
Turn-Over or Trip-OverTurn-Over or Trip-Over
• Heavier damage to right side of roof indicates that the left side was probably leading.
• Damage to left side wheels verifies that the left side was leading and that it is a Trip-Over rather than a turn-over.
Climb-OverClimb-Over
Vehicle climbs up and over a fixed object such as a barrier or guardrail
Fall-OverFall-Over
Vehicle is tipped by slope so that its center of gravity is outboard of its wheels.
Fall-Over?Fall-Over?
Fall-Over or Trip-Over?Fall-Over or Trip-Over?
Left Side Wheel DamageLeft Side Wheel Damage
Close-up LF Wheel DamageClose-up LF Wheel Damage
Fall-Over or Trip-Over?Fall-Over or Trip-Over?
• Note left side wheel damage• Indicates that the left side was leading• Verifies that this is a trip-over rather
than a fall-over
Bounce-OverBounce-Over
Vehicle rebounds off fixed object (such as a guardrail), and overturns as a consequence
Instead of rebounding, the vehicle climbs over the fixed object (such as a guardrail), and overturns on the opposite side
However, IfHowever, If
It becomes a?Climb-Over
Impact With Another Impact With Another VehicleVehicle
Rollover is the immediate result of an impact with another vehicle.
Momentum from the impact causes vehicle to turn-over, no tripping is involved
Vehicle Impact Vehicle Impact or or
Trip-OverTrip-Over
RightRight Right RightRearRear Front Front
Left Side Roll DamageLeft Side Roll Damage
Roll and LR Wheel DamageRoll and LR Wheel Damage
Roll and LF Wheel DamageRoll and LF Wheel Damage
Left FrontLeft Front Left RearLeft Rear
Vehicle Impact or Trip-OverVehicle Impact or Trip-Over
• Vehicle/vehicle impact was the impetus to send this vehicle into curb but,
• The curb impact was the initiator for the rollover and thus this is a TRIP-OVER.
Tripped or Untripped?Tripped or Untripped?
Left FrontLeft Front Left RearLeft Rear
ConclusionConclusion
• Scrutiny of both scene evidence and vehicle damage -- especially the wheels is critical.
• Close-up images of the wheels are very important.
QuestionsQuestions