Using SHRP 2 naturalistic driving data to assess drivers' speed choice while being engaged in different secondary...

Area of Science:

• Human-Computer Interaction
• Traffic Safety
• Cognitive Psychology

Background:

• Secondary task engagement while driving impairs performance and increases crash risk.
• Texting is a primary concern due to its association with increased accident rates.
• Drivers employ self-regulation strategies, such as reducing speed, to mitigate risks.

Purpose of the Study:

• To investigate if drivers adjust their speed during secondary tasks under naturalistic driving conditions.
• To compare speed adjustments across various secondary tasks (texting, smoking, eating, radio/climate control).

Main Methods:

• Analysis of data from the SHRP 2 naturalistic driving study.
• Focus on free-flow driving episodes on interstates/highways to control for confounding factors.
• Examination of driving speed before, during, and after engaging in secondary tasks (403 episodes).

Main Results:

• Some indication of speed reduction during texting, particularly at higher speeds, but with small effect sizes.
• Significant variation in behavioral patterns among individual drivers.
• No significant influence of smoking, eating, or radio/climate control adjustments on driving speed.

Conclusions:

• While minor speed adjustments may occur, strategic self-regulation likely plays a larger role in naturalistic driving.
• Naturalistic driving data is valuable for studying driver self-regulation.
• A mixed-method approach is recommended for a comprehensive understanding of driver behavior.