Dr. Charles Jennissen, with the University of Iowa's Department of Emergency Medicine presented this at CPSC's ATV Safety Summit Oct. 12, 2012. The Safety Information and Guidance Provided to Parents by All-Terrain Vehicle Dealers and Sales Representatives' Objective: To determine the practice of ATV dealers and salespersons with respect to providing safety information since enactment of the 2009 U.S. Consumer Product Safety Improvement Act. Methods: A "secret buyer" method was utilized to evaluate seller practices. Results: 50 dealerships from 4 states were studied. 35 subjects (70%) were willing to show and discuss selling an adult-sized ATV when told that the purchase was for a 12 year old. Seven (14%) responded that ATVs should not have extra riders when the investigator made statements about the adequacy of a seat being long enough for a child to give a sibling rides. Only one subject, when prompted, informed the investigator about the need for a 12 year old to complete ATV safety training to drive in a public ATV park. Conclusions: Most ATV sellers in this study failed to follow requirements regarding age recommendations or to provide other safety information. Those who did often voiced concerns about possible negative repercussions from violations. Dealership compliance would likely benefit from increased enforcement, training, and resources. However, a "don't ask, don't tell" relationship between seller and buyer was alluded to during the study. This practice would predictably limit the impact of regulation enforcement.

1. Determining Rider-Vehicle Dynamics
Utilizing an ATV Simulator
Charles Jennissen, MD
Gerene Denning, PhD
Department of Emergency Medicine,
University of Iowa Carver College of Medicine
Salam Rahmatalla, PhD
Environment and Civil Engineering,
Jonathan DeShaw, MSE
Biomedical Engineering
University of Iowa College of Engineering
1

2. Background
 University of Iowa and the College of Engineering has very
strong computer modeling and simulator programs.
2

3. Virtual Soldier
 Santos, a high fidelity avatar
 Biomechanical musculoskeletal
modeling along with predicative
dynamics technology
 Can deliver feedback on how a
certain type of task or combination
of movements will impact a
human's level of fatigue, speed,
strength and torque over a period
of time.
3

4. Center for Computer Aided Design
4

5. Hank Virtual Environments Lab
 Focuses on using virtual
environments to study human
perception and action.
 Understand how children and
adults negotiate traffic-filled
intersections in our virtual
environment.
 Understand how people
perceive and adapt to virtual
environments.
 Factors that put children at risk
for getting hit by motor vehicles
when crossing intersections
5

6. National Advanced Driving Simulator (NADS)
 One of the two most sophisticated
driving simulators in the world.
6

7. MiniSim
 Harnesses the technological sophistication of NADS in a
compact, customizable configuration.
 Can be rapidly deployed for off-site or multi-sited research,
population-specific assessment, or driver training.
7

8. NADS
Looking at the role of cognitive development
in safe tractor operation.
8

9. 3D Bio-Motion Research Lab
Performs applied and basic research in human
motion and biomechanics.
Moog ECU-624-1800
Electric Motion System
 A tilt/vibration platform that is
capable of acceleration of up to
15 m/s² in the longitudinal, lateral,
and vertical directions.
(Simulate Speed)
 Can generate angular motion of
at least 20 degrees in the roll,
pitch and yaw directions.
(Simulate Sloped Terrain)
 Can vary vibration frequncies.
(Simulate Rough Terrain)
9

10. 3D Bio-Motion Research Lab
Moog Electric Motion
System
State of the art motion
tracking equipment including
a Vicon system with 12 SV
cameras and a Motion
Analysis system with 16
Eagle-4 cameras.
10

11. ATV simulator
Bought a non-functioning
Yamaha Bruin 4x4 ATV.
Stripped the tires and
modified it so that the
ATV could be secured to
the motion platform.
11

12. ATV simulator
Created a padded
protective structure
around the ATV that
could be secured to the
motion platform.
12

13. Objective
Determine inter-individual variability in the
biomechanical parameters of experienced adult
operators with regards to operator/vehicle dynamics
using an adult sized ATV simulator
13

14. Subjects
6 adult males
18-45 years of age
Within one standard deviation of mean height
and weight for an average adult male
≥100 hours of ATV operating experience
14

15. Methods
 Reflective markers were placed on the
subjects (24) and on the vehicle (4).
 Accelerometers placed on helmet and at
C7
 A series of seven programs were
performed by each participant with
changes at a variety of accelerations.
 2 identical pitch programs
(incline/decline)
 2 identical roll programs (side hill/side to
side)
 2 identical vertical change programs
(hole/bump)
 1 program with all elements
 Small vibrational motion in 6 degrees of
freedom used as physical distraction and
to mimic normal vehicle vibration
 Movie of ATV riding through wooded area
used as mental distraction
15

16. Methods
Subjects were video
recorded from the back
and side.
Vicon motion capture system recorded motion
of the subject from the pelvis and above
Motion data analyzed with Visual 3D™
Software which is NIH approved
16

17. Pitching Motion - Video

18. Pitching Motion – Motion Capture

19. Pitching Motion – Motion Capture

20. Pitching – At Time of Largest Motion
Subject 1 & Repeat Subject 2 & Repeat Subject 3 & Repeat

21. Pitching – At Time of Largest Motion
Subject 4 & Repeat Subject 5 & Repeat Subject 6 & Repeat

22. Pitching – Angle Between Torso and ATV
AVERAGE 4 Point: C7 to Pelvis to 4 Wheeler Angle
80
Sub1
Sub1 Repeat
Side View 70
Sub 2
Sub 2 Repeat
Sub3
Sub3 Repeat
60 Sub 4
Sub 4 Repeat
Sub5
Sub5 Repeat
50 Sub 6
Angle - (Degrees)
Sub 6 Repeat
40
30
20
10
0
0 50 100 150 200 250 300 350 400
Cycle, Time = 2 Seconds

23. Rolling Motion - Video

24. Rolling Motion – Motion Capture

25. Rolling Motion – Motion Capture

26. Rolling – At Time of Largest Motion
Subject 1 & Repeat Subject 2 & Repeat Subject 3 & Repeat

27. Rolling – At Time of Largest Motion
Subject 4 & Repeat Subject 5 & Repeat Subject 6 & Repeat

28. Rolling – Angle Between Torso and ATV
AVERAGE 4 Point: C7 to Pelvis to 4 Wheeler Angle
40
Sub1
Sub1 Repeat
Sub 2
Sub 2 Repeat
Front View Back View 30 Sub3
Sub3 Repeat
Sub 4
Sub 4 Repeat
Sub5
Sub5 Repeat
20
Sub 6
Sub 6 Repeat
10
Angle - (Degrees)
0
-10
-20
*Measured degrees from vertical
Angle from C7 to the center of the pelvis to
the ATV -30
0 50 100 150 200 250 300 350 400
Cycle, Time = 2 Seconds

29. Roll Motion – Accelerations at C7

30. Roll Motion – Change of Force at C7

31. Future Studies
 Will add pressure sensors on the handle
grips, seat, and footrests to provide
additional biomechanical measurements.

32. Conclusions
 Our preliminary data provides proof-of-
principle for using our simulator to study
“active riding.”
 Future studies include determining how
factors such as gender, age, inexperience,
and passengers influence rider-vehicle
dynamics.
 Simulator-based technology is a powerful
and safe tool to address research questions
related to ATV operation that cannot be
tested using other methods.