EVALUATING DISTRACTION AMONG DRIVERS USING MOBILE DEVICES
Contextual inquiry // Ethnography // Usability // Eye-tracking // Mixed-methods
About this project:
Drivers and their vehicles are becoming more connected with technology. Many drivers use their mobile devices on the road, so guidelines exist to regulate what is considered “safe” while driving. This project, funded by the National Highway Traffic Safety Administration, sought to evaluate whether common tasks violate current metrics for distraction.
The National Highway Traffic Safety Administration (NHTSA) is responsible for developing and maintaining guidelines around what constitutes “safe” in-vehicle tasks, such as placing a phone call, following mapping directions, or engaging in voice-to-text operations.
According to NHTSA, driver distraction occurs when drivers divert their attention away from the driving task to focus on another activity. These distractions can be categorized in terms of visual, manual, and cognitive.
As NHTSA prepares to update and expand regulations around visual and manual distraction, this project served to provide insights about the current experiences of drivers who regularly interact with technology while driving. My role was to design and conduct evaluative research exploring these current user experiences.
Design a series of studies to evaluate current patterns among individuals who use cell phones for common tasks while driving.
Compare observations to existing guidelines to evaluate compliance.
Assess whether existing “driver-mode” apps are effective in minimizing distraction.
Contextual in-vehicle interviews and usability evaluations during drive alongs with 25 “heavy” users
Commonly engage in a variety of tasks using their mobile device while driving, such as texting, mapping, POI searching, playing music, etc.
Valid US driver's license
Used their own vehicle
All handheld smartphone users (no mounted phones)
Do not pair their phone with their vehicle
In-vehicle driving sessions included:
Think-aloud cognitive interview to examine the behaviors and strategies of frequent phone users while driving
Usability drive for task strategies, task times, eye-glances, and problem coding for distraction
Post-drive interview for qualitative feedback
"Driver mode" app introduction and discussion (Session 1)
"Driver mode" reflection (Session 2)
Sessions were conducted on a half-mile one-lane roadway loop that was closed to the public during experimental sessions. Comfortable driving speed on this road was up to 25 mph. The intent of the road choice was to require participants to engage in the normal driving tasks of path maintenance and roadway scanning while traveling in a safe environment.
Quantitative measures in consideration with current guidelines
Qualitative measures to evaluate strategies and problems
INSIGHTS AND TAKEAWAYS
Though task times and glance times vary considerably across different tasks, no tasks (on average) met the current NHTSA Visual-Manual Driver Distraction Guidelines criteria across all metrics.
Total device glance time (s)
Phone placement choices reflected dual motivations to enact tasks easily and appear compliant with regulations.
“I don’t want to be caught on the phone and get a ticket, so I hold the phone down low on speakerphone.”
“Using two hands to type is twice as fast because it’s twice the fingers.”
Some drivers utilized their own strategies to minimize distraction and limit temptation to use their devices.
“Sometimes I’ll leave my phone in my purse or in the trunk. If it’s out of sight, there's less temptation for me to use it while driving.”
“I only use my phone at stop lights.”
“I use voice commands and I try to phrase the command very clear so that the phone will understand me.”
A “driver mode” interface has the potential to reduce driver distraction.
Driver mode interfaces can include features such as a simplified home screen, reduced access to tasks or apps than can be customized by each user, automatic launching, bypassing screen timeout and PIN code requirements, and allowing users quick access to complete common tasks.
“If there was a driving mode that made everything bigger and shuts off distracting features from the phone while I’m driving, that would be a good thing.”