Trust in Autonomous Vehicles: A Simulator Study

Lindsay H. Ryan, PhDInstitute for Social Research

University of Michigan

The Future of Automotive Safety Conference, UMTRI Automotive Futures Group 2018

Acknowledgements

• Mobility Transformation Center

Funding

• Project Team: PI Lisa Molnar, Co-

Investigators Anuj Pradhan, David Eby,

Renée St. Louis, and Jennifer Zakrajsek

• Additional assistance from Nicole

Zanier and Dana Demchak

Aging Drivers in

the United States

Intersection of Age and Technology

Implications for Trust in Automated

Vehicles

Does experience with other tech matter?

Do beliefs about other drivers matter?

Does actual experience using automated tech matter?

Pilot Study

• Three main components– Level 3 Autonomous Car Simulator– Structured Interview– Self-administered Questionnaire

• Three groups: novice drivers (16 – 19), older drivers (65-75), and comparison group (age 25 – 45)

• Primary focus was on transfer of automated-to-manual control and vice-versa

UMTRI High-fidelity Advanced Driving Simulator

Simulation Design1. Eye tracking calibration2. 10 minute practice, manual and automated3. 20 minute main drive– Begin in manual mode– Instructed to engage automated mode when

comfortable– 8 points during drive prompt automated-to-manual

control change– Timing to re-engage automated mode was up to the

driver

Structured InterviewContent– Expectations about autonomous vehicles before and

after the simulator experience– Comfort with different driving situations in simulator– Difficulty managing transitions – What did you do during automated mode?– Did you trust the automated driving?– Any concerns if this type of tech was available in the

real world?– Are you interested in having a vehicle with this

technology?

Driver Age GroupsDemographics and Driving

Characteristics16-17 25-45 65-75 All

Number of participants 24 24 24 72

Mean age (SD) 16.4 (.50) 33.5 (5.9) 68.8 (3.6) 39.6 (22.2)

% Female 50.0 50.0 45.8 48.6

Avg. days driven per week 5.3 6.1 6.1 5.8

Avg. miles driven per week 79.5 158.7 133.4 123.9

Someone available to give you rides (%) 100.0 79.2 79.2 86.1

Someone depends on you to drive them

(%) 33.3 33.3 33.3 33.3

Indicators of Trust

• Simulator Behavioral Indicator: % of manually driven simulator scenarios– # automated-to-manual

transitions missed due to manual driving

• Self-report Indicator: “Did you trust the automated driving? Why or Why not?”– Coded: 0 = No, 1 = Situation

specific, 2 = Yes

Individual Driver

Characteristics

Comfort with other drivers: “Are you usually comfortable with other people behind the wheel?”

General control preferences: “Generally speaking, do you like to have control over things?”

Experience with other technology: Count of various technologies used

Themes that Emerged from the Interviews

Rural, low traffic, straight driving were the contexts where most drivers were comfortable with the automated mode

Older Drivers Interested in Automated Technology to Extend mobility

Beliefs about Other Drivers and Technology Matter

• In favor of automated vehicle technology

Worried about distracted

drivers

• Not in favor of automated technology

Worried drivers won’t pay

attention during Automated

Mode

Impact of the News/Media

Predictors of Trust in Automated Technology

• Drivers who reported ↑comfort with other drivers behind the wheel also reported ↑ trust in automated drive technology (B = .25, p < .05)

“Did you trust the automated driving? Why or Why not?”

• Coded trust in automated driving was only significant predictor (B = -.15, p < .01)

• Partial validation of this behavioral indicator

% of manually driven

simulator scenarios

Future Directions

• New validated measures of trust in automated vehicles are needed

• Need to test these associations in real-world settings with diverse driver samples– E.g. Samples with less

education and less experience with other technology