AUTONEWS

Speed and low-light conditions linked to drivers skipping seatbelts

In 2021, motor vehicle crashes were one of the leading causes of death in the United States, accounting for 42,939 deaths nationwide (Stewart, 2023). Many road fatalities are attributed to human factors, such as speeding, impaired or distracted driving, and failure to wear a seat belt (Stewart, 2023, National Highway Traffic Safety Administration, 2022). Studies have shown that seat belts are one of the most effective countermeasures for minimizing crash-related injuries (Blincoe et al., 2010, Lee and Schofer, 2003, National Center for Statistics and Analysis, 2016). Seat belts alone saved 14,955 lives in 2017 and may have protected an additional 2,549 if used (National Center for Statistics and Analysis, 2017). Seat belts for front-seat passengers can reduce fatal injuries by 45 % and moderate-to-severe injuries by 50 %, according to the National Highway Traffic Safety Administration (NHTSA) (National Center for Statistics and Analysis, 2016). 

Despite the safety benefits of seat belts, a considerable number of drivers and passengers continue to travel unrestrained. A recent nationwide seat belt data revealed that the nationwide non-compliance rate was 8.1 % for all occupants, 7.9 % for drivers, and 10.0 % for front-seat passengers (National Center for Statistics and Analysis, 2024). In the same year, 51 % of the 23,824 occupants killed in car crashes were not wearing seat belts (National Highway Traffic Safety Administration, 2022). Since not wearing a seat belt or non-compliance with seat belt laws is a critical safety issue, an in-depth analysis of seat belt compliance is needed.

Seat belts are among the most basic and effective in-vehicle safety measures. Yet, understanding seat belt compliance and seat belt use behavior remains a complex issue that spans multiple disciplines. Research on this topic involves contributions from healthcare, computer science, psychology, human factors, law, and other fields. Over the past two decades, numerous studies have investigated various aspects of seat belt use (Aidoo et al., 2021, Farooq et al., 2021, Hezaveh et al., 2019, Høye, 2016, Lerner et al., 2001, Raman et al., 2014, Shaaban and Abdelwarith, 2020, Steptoe et al., 2002). To address the problem of seat belt non-compliance, it is crucial to discuss each component of seat belt use behavior.

Previous research has taken different approaches to this issue. Some articles and reports have focused on the factors associated with seat belt use, while others have emphasized education and awareness campaigns. Certain studies have concentrated on detecting seat belt compliance, and others have used self-reported surveys and crash reports to investigate usage.

In terms of review studies, researchers have examined seat belt use from various perspectives. For example, a recent study by Agarwal, Kidambi, and Lange reviewed the evolution of seat belts, highlighting technological advancements, regulatory changes, and future trends, particularly with the advent of vehicle automation (Agarwal et al., 2021). Kargar et al. conducted a meta-analysis on the prevalence of seat belt use, examining factors influencing compliance and the effectiveness of interventions (Kargar et al., 2023).

Despite the ample research on seat belt compliance and seat belt use, a systematic review that encompasses all components associated with seat belt use and compliance behaviors is missing from the literature. These components include factors influencing seat belt usage behavior, various techniques to collect and analyze seat belt use, and measures to improve compliance. This study aims to fill this gap by synthesizing the comprehensive literature on seat belt use and compliance, identifying gaps, and recommending future research directions to improve this critical safety habit.

Another essential objective of this study is to compile a summary of findings from the extensive literature review. These findings highlight the state of knowledge on data collection, data analysis, contributing factors, and measures to improve seat belt compliance since the year 2001. This summary will be invaluable for engineers, practitioners, and policymakers in proposing appropriate measures to enhance seat belt compliance.

In contrast to previous review studies, this research specifically aims to provide a comprehensive review of “seat belt use and compliance behavior” over the last 23 years, focusing on driver demographics, roadway design, trip features, and temporal variables. This study also aims to explore modern data collection methods and advanced technologies like Deep Learning (DL) for compliance detection. This approach offers a broader understanding and practical recommendations for enhancing seat belt usage, distinct from the scope of earlier studies.

This paper is organized as follows. The first section is the introduction, which provides an overview of seat belt non-compliance behavior. It is followed by the ‘Research Methodology’ section, which describes the systematic contributors to seat belt compliance studies. The next section is the Results section, which includes multiple subsections. The first subsection focuses on summarizing the trend of seat belt compliance rates across the globe. The next subsection presents an overview of various studies focusing on collecting seat belt usage data. An overview of different data analysis methods used to explore seat belt use and compliance behavior is illustrated in the following subsection. 

The subsequent subsection describes the factors associated with seat belt use and compliance. A comprehensive review of the measures taken to ensure seat belt use is presented in the final subsection. Before the conclusion, a 'Discussion' section is provided to examine the current trends in seat belt compliance research, the interconnections between components of seat belt use and compliance research, gaps in the existing literature, possible policy recommendations, and future research opportunities. The last section is the conclusion, which highlights the summary of seat belt research and the gaps in the literature on seat belt use and compliance studies.

Drivers were less likely to wear seatbelts at night, at higher speeds, and on shorter trips, suggesting safety campaigns may be more effective when they target the situations in which people are most likely to skip buckling up.

Drivers who don’t wear their seatbelts were found to be doing it in situations when seatbelts would actually help the most, according to a new study by researchers from the Penn Medicine Nudge Unit. The analysis, published in Traffic Injury Prevention, highlighted that situations like driving after sundown or even at high speeds were more predictive of whether someone skipped a seatbelt than their demographics.

“Our study suggests that future seatbelt campaigns and other interventions may be more effective if they move beyond broad demographic targeting and, instead, focus on these moments when people are most likely to skip buckling,” said senior author M. Kit Delgado, MD, faculty director of the Nudge Unit and an associate professor of Emergency Medicine.

Seatbelts cut the risk of death and serious injury...Seatbelt usage has been found to cut people’s risk of death or serious injury in half, but one in 10 of those riding in the front seats of a vehicle don’t use them. As such, almost half of crash fatalities in the United States involve a person not wearing their seatbelt.

Delgado, lead author Jeffrey Ebert, PhD, director of Applied Behavioral Science at the Nudge Unit, and their colleagues decided to see if there were some commonalities in who didn’t use seatbelts and what situations non-usage of seatbelts occurred in.

Looking at data from 1,000 consenting participants over almost 130,000 trips­—gleaned from vehicle sensors, including ones in seatbelt latches—the researchers found that most people did use their seatbelts. Of all trips recorded, 84 percent included seatbelt use.

However, when a seatbelt was not used on a specific trip, the researchers determined that it was unrelated to the driver characteristics like sex, age, or where they lived. Instead, it was the details of the trip that mattered.

Drivers buckle up less at night and at higher speeds...The data showed that 30 percent of buckling behavior could be tied to “situational factors,” while not even 1 percent could be tied to demographics.

Drivers were 6 percent less likely to wear a seatbelt in the evening, and 13 percent less likely late at night.

For any given driver, a 10 mile-per-hour increase in speed was tied to a 2 percent drop in buckling.

Looking at when drivers did use their seatbelts, longer trips correlated with greater seatbelt use. The data showed that 74 percent of drivers taking a trip of five miles or less wore their seatbelts, but 95 percent buckled on longer trips.

Identifying a more targeted intervention...Currently, campaigns for seatbelt buckling are largely targeted widely, such as through electronic billboards and “Click-it or Ticket” advertisements.

But the Nudge Unit’s work points to an opportunity to more effectively reach people in situations where they might need the message.

At the same time, the team said that roughly 25 percent of individuals’ tendency to buckle up couldn’t be pinned down to a factor measured in the study. More research could potentially narrow down these unknown variables—which could include non-demographic considerations like personality traits—and lead to better interventions.

“The more we know about when people buckle up—and when they don’t—the more lives will be saved,” Ebert said.

The team has already had success in getting more drivers to buckle up. Offering cash incentives in a “game” challenging drivers to stack up seatbelt streaks resulted in more drivers using their seatbelts, even after the game ended.

“We have tested ways that seem effective in promoting this safer behavior,” Delgado said. “Combining all available information and our work in nudging appears especially promising.”

by: Frank Otto(Francis.Otto@pennmedicine.upenn.edu)

Penn Medicine Nudge Unit