Does Older Adults’ Self-Regulation of Driving Improve Safety? An Examination of Objective and Subjective Driving Patterns in the AAA LongROAD Study

Abstract

Introduction

Self-regulation is the act or process of modifying one’s driving in response to an awareness of one’s declining abilities. Two common forms are (1) strategic self-regulation, or decisions made prior to one’s actual driving, and (2) tactical self-regulation, decisions made while driving in response to circumstances of the environment. Rapid Deceleration Events (RDEs), commonly known as hard braking events, are used as a proxy for unsafe driving. The present study assessed the relationship between strategic and tactical self-regulation of driving and RDEs and self-reported crashes. It was hypothesized that increasing levels of self-regulation would be associated with fewer RDEs and self-reported crashes.

Methodology

This research brief used data from a prospective cohort study of 2,990 older adults aged 65–79 years old at the time of enrollment across five geographically diverse study sites in the U.S. Over the five years of data collection, participants completed an annual survey, which inquired into demographic information and 20 various alterations to driving behavior. Motivations for changes in driving behavior were analyzed and categorized as either tactical self-regulation or strategic self-regulation. Participant vehicles were each equipped with a datalogger device that recorded GPS information when the vehicle ignition was activated. Rapid Deceleration Events (RDEs) were calculated from the longitudinal acceleration derived from the GPS data with lower thresholds of 0.40g (RDE40) indicating less severe braking by the driver and higher thresholds of 0.75g (RDE75) indicating more severe braking. Additionally, at the end of each study year, participants self-reported the number of crashes they experienced (as a driver) in the past year. Rates of RDE40s were calculated per 1,000 miles driven, while binary variables were calculated to indicate whether a participant had experienced at least one of each of the much less frequent outcomes, RDE75s or self-reported crashes, in a given year. The final sample analyzed was reduced to 2,363 participants for which there was complete and available datalogger data.

Key Findings

Over the course of the study, for which there was complete and available datalogger data, a total of 48,982 RDE40s and 185 RDE75s were recorded. Nearly all participants (96%) reported engaging in at least 1 of 7 tactical self-regulation behaviors, and 81% of participants reported engaging in at least 1 of 13 strategic self-regulation behaviors. A total of 507 crashes were self-reported with 16.2% of participants in the sample reporting experiencing a crash at some point during the years for which they had complete and available datalogger data.

No single tactical or strategic self-regulation item was associated with all three safety outcomes—RDE40s, RDE75s, and self-reported crashes. Four tactical self-regulation items and six strategic self-regulation items were associated with the occurrence of RDE40s. Three tactical self-regulation items and three strategic self-regulation items were associated with the occurrence of RDE75s. Only one tactical self-regulation item and one strategic self-regulation item were associated with the occurrence of self-reported crashes. When adjusting for various factors, analyses indicated that neither tactical nor strategic self-regulation sum scores predicted the occurrence of RDE40s, RDE75s, or crashes.

Despite a lack of statistically significant findings, older drivers should continue to implement and practice self-regulatory behaviors into their daily driving habits. These behaviors may increase their safe mobility, especially their ability to safely operate a vehicle, and may serve as a useful tool for individuals having conversations with older drivers about the aging process and driving.