Dissertation
Testing and use of a PC-based tractor driving simulator to examine the impact of age and hypertension medication on selected driving performance measures
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Spring 2020
DOI: 10.17077/etd.005399
Abstract
Transportation related incidents are the leading cause of occupational fatalities for all industries in the United States, including the agricultural industry which suffers thousands of crashes involving farm equipment each year. Simulated driving studies offer a safe and cost-effective way to conduct driving research that would not be feasible in the real world. A tractor driving miniSim™ emulating a John Deere tractor cab with realistic controls was developed and then evaluated for realism at the University of Iowa among 99 Midwestern farm equipment operators. It was then used to examine the associations of age and hypertension medications with driving performance.
After completing a 10-minute drive, farm equipment operators completed a survey and scored four specific domains assessing specific characteristics (i.e., Appearance, User Interface, Control, and Sound) of the tractor simulator’s realism using a 7-point Likert scale (i.e., 0=not at all realistic, 6= completely realistic). An overall realism score and domain scores were calculated. Farm equipment operators were also asked to provide recommendations for improving the tractor miniSim. Farm equipment operators then completed a main study drive during which an incurring semi presented a driving hazard. Perception response time was collected and analyzed for its association age and use of hypertension medication.
Overall, farm equipment operators rated the simulator’s realism favorably (i.e., >3 on a scale between 0 and 6) for all individual items and domains. The Appearance domain received the highest average realism score (mean=4.58, SD=1.03), and the Sound domain received the lowest average realism score (mean=3.86, SD=1.57). We found no significant differences in realism scores across farm equipment operator characteristics. The most frequently suggested improvements were to tighten the steering wheel (27%), make the front tires visible (19%), and that no improvements were needed to improve simulator realism (18%).
This dissertation established the new tractor miniSim as a viable approach to studying farm equipment operations and events that can lead to tractor related crashes. Furthermore, this dissertation demonstrated that senior farm equipment operators responded 3.71 [95% CL= -1.35, 8.78] seconds slower than younger farm equipment operators. When adjusted for selected medical diagnoses and medications, tractor generation and tractor horsepower senior farm equipment operators responded 5.00 [95% CL=-1.23, 11.24] seconds slower than younger farm equipment operators. Similarly, senior farm equipment operators who were taking hypertension medication had perception response times 5.73 [95% CL= -2.19, 13.64] seconds slower than those not taking hypertension medications. When adjusted for history of tobacco use, impairing medical diagnoses, and handedness, senior farm equipment operators taking a medication to treat hypertension responded 6.47 [95% CL= -5.10, 18.04] seconds slower than those not taking a hypertension medication.
While not statistically significant, the increased response times demonstrated in this dissertation are large considering their implications with crash avoidance. A tractor traveling at 20 mph can travel approximately 190 feet in the 6.47 seconds it may take for the driver to respond to the hazardous event, greatly increasing the risk for a crash.
Details
- Title: Subtitle
- Testing and use of a PC-based tractor driving simulator to examine the impact of age and hypertension medication on selected driving performance measures
- Creators
- Kayla Faust
- Contributors
- Carri Casteel (Advisor)Daniel McGehee (Committee Member)Corinne Peek-Asa (Committee Member)Diane Rohlman (Committee Member)Marizen Ramirez (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Occupational and Environmental Health
- Date degree season
- Spring 2020
- Publisher
- University of Iowa
- DOI
- 10.17077/etd.005399
- Number of pages
- xii, 131 pages
- Copyright
- Copyright 2020 Kayla Faust
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references.
- Public Abstract (ETD)
Transportation related incidents are the leading cause of occupational fatalities for all industries in the United States, including the agricultural industry which suffers thousands of crashes involving farm equipment each year. Simulated driving studies offer a safe and cost-effective way to conduct driving research. A tractor driving miniSim™ was developed and then evaluated for realism among 99 tractor drivers. It was then used to examine how age and hypertension medications affect driving performance.
Participants rated the simulator’s realism and were asked to provide recommendations for its improvement. During the study, participants encountered a semi at an intersection requiring them to reduce their speed to avoid a collision. Response time was collected and analyzed for its association with age and hypertension medication use.
Participants rated the simulator’s realism favorably. We found no significant differences in realism scores across tractor driver characteristics. The most frequently suggested improvements were to tighten the steering wheel and make the front tires visible. Furthermore, we demonstrated that senior tractor drivers responded approximately 5.00 seconds slower than younger tractor drivers regardless of selected medical diagnoses and medications, tractor generation or horsepower. Similarly, senior tractor drivers taking hypertension medication responded 6.47 seconds slower than those not taking hypertension medications regardless of tobacco use, impairing medical diagnoses, and handedness.
The increased response times in this dissertation are large considering a tractor traveling at 20 mph can travel approximately 190 feet in the 6.47 seconds it may take for the driver to respond, greatly increasing the risk for a crash.
- Academic Unit
- Occupational and Environmental Health
- Record Identifier
- 9983949691502771
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