Measuring Cognitive Distraction in the Vehicle Joel Cooper Precision Driving Research David Strayer University of Utah Trends and usage Evaluated 403 vehicle models from top 14 manufacturers • 98.3% offered Bluetooth pairing • 89.8% screen in center stack • 50.4% offered smartphone application integration. • 94.3% offered a USB port Available functions • Make Calls • Send and received text messages • Send and receive emails • Update social media • Control radio, climate, gps, etc. The Driver Distraction Triad Visual: Eyes off the Road High Moderate Low Manual: Hands off the Wheel Cognitive: Mind off the Drive Trends and Questions • The Apps are coming… • Hands and eyes free is increasingly seen as the solution to visual distraction Generally speaking, the same task will be less dangerous if it can be achieved via an auditory / vocal interactions rather than visual / manual interactions. However… Potential risk is momentary demand and exposure Q: Are the potential risks of some auditory/vocal tasks greater than others? Overview of AAA Project • Most comprehensive study undertaken on mental workload • Systematic analysis, 3 studies, 150 participants, 8 conditions • Analysis of different sources of distraction • Driving simulator • Instrumented vehicle • Develop taxonomy of cognitive mental workload • Category 1 – Workload associated with Baseline Driving • Category 5 – Workload associated with Highly Demanding Secondary task Sources of Cognitive Distraction • • • • Baseline Driving Listen to Radio Audio Book Passenger Conversation • • • • Hands-free cell conversation Hands-held cell conversation Speech-to-Text task Mental Math (OSPAN) Evaluation Platforms Measures • Primary • Secondary • Physiological • Subjective Developing a Metric of Cognitive Workload • Problem: Measuring cognitive workload is notoriously difficult • Objective: Develop robust instrument of cognitive distraction • Older technologies (e.g., radio, cell phone, etc.) • Newer technologies (e.g., speech-based in-vehicle communication) • Standardized rating system • Similar to other rating systems (e.g., Richter, Saffir-Simpson, etc.) where higher ratings are indicative of greater cognitive distraction Video of Instrumented Vehicle Brake Reaction Time Scanning for Hazards at Intersections NASA TLX – Mental Workload Cognitive Workload Scale What does this mean in terms of risk? Increases in mental workload led to: • Reduced visual scanning for hazards • Reduced brake response time • Reduced attentional capacity (as measured by the p300 ERP) • Mental Workload Distraction • Mental Workload Risk What does this mean in terms of risk? From other research However… • • • • • • • • Inattentional blindness Impaired judgment and decision making General reduction in visual scanning Reduced frequency of lane changes Reduced stopping at intersections • Reduced fatigue Reduced boredom Improved lane maintenance Increased visual attention toward forward roadway Summary of Results • Category 1: Baseline, Radio, Book • Category 2: Conversations (HH, HF, Passenger) • Category 3: Text to Speech • Category 5: Mental Math Summary and Results • Proceed with caution! • Text-to-Speech systems may be more mentally demanding than conversations. Low frequency/ high risk potentially equal to high frequency/ low risk Future Directions • How does the quality of speech affect workload? • How do errors in understanding affect workload? • How does an actual system, such as Siri, fit on the scale? • Are structured interactions more/less demanding than unstructured interctions? Thank You!