The impact of police presence on angry and aggressive driving

Speed kills? Quantifying the association between police traffic stops, types of stops, and motor vehicle collisions

BACKGROUND

Motor vehicle crashes (MVCs) are a leading cause of traumatic death and injury. Police traffic stops (PTS) are a common approach to enforcing motor vehicle laws intended to prevent MVCs. However, it is unclear which types of PTS are most effective. This study examined the relationship of PTS subtypes among municipal police patrols on non-interstate roads and MVCs and MVC-related deaths.

METHODS

PTS subtype data were characterized from six North Carolina cities: Charlotte, Durham, Fayetteville, Greensboro, Raleigh, and Winston-Salem. The primary outcomes of this study were yearly non-interstate MVC and MVC-related death rates per 100 population. The data were analyzed as balanced time-series cross-sectional data. The statistical analysis accounted for time-dependent and city-dependent confounding. We used a two-way fixed effects model to analyze the relationship between PTS and MVC or MVC-related deaths. We also utilized the difference in difference (DID) analysis to analyze if the reduction of PTS following a 2012 policing administrative change in Fayetteville had an association with MVC or MVC-related deaths.

RESULTS

We found no significant overall association between non-interstate PTS and MVCs (Coeff: -0.00006; p = 0.43) or MVC-related deaths (Coeff: -0.00011; p = 0.15). Panel regression suggested no significant relationship between MVCs and MVC-related deaths and PTS related to driving while impaired (p = 0.36), safe movement violation (p = 0.43), or seatbelt violations (p = 0.17). However, speed limit violations (Coeff: -0.00025; p = 0.032) and stop-light/sign violations (Coeff: -0.00147; p = 0.017) related to PTS significantly reduced MVC-related deaths. The DID regression showed no significant impact on MVCs (p = 0.924) or MVC-related deaths (0.706) before and after the police reform period.

CONCLUSIONS

The evidence regarding the absence of an overall association and any association with most PTS subtypes suggest that PTS are not effective for MVC death prevention. Policymakers may proceed with exploring modifications to policing efforts without detriments to public safety as defined by MVC and MVC-related deaths.

LEVEL OF EVIDENCE

Retrospective epidemiological study, level IV.

Evaluation of a Road Safety Awareness Campaign Deployed along the Roadside in Saguenay (Québec, Canada)

For the past few years, police officers from the City of Saguenay have been installing a billboard combined with a damaged car along roadsides to make drivers aware of the road risks related to dangerous behaviors at the wheel. To assess the short-term effect of this device, evaluative research with a quasi-experimental design with pre-exposure, during, and post-exposure. The results show a significant decrease (p < 0.001) of 0.637 km/h for the first site (a 70 km/h zone) and 0.269 km/h for the second site (a 50 km/h zone) when the device is exposed. At the time of this last evaluation, a reduction of 1.255 km/h remained even after the advertising panel was removed. Although minimal, this speed reduction where the billboards are placed shows the police that this awareness-raising approach works since it reduces the speed of motorists at very low cost.

The relationship between aggressive driving and driver performance: A systematic review with meta-analysis

Traffic crashes remain a leading cause of accidental human death where aggressive driving is a significant contributing factor. To review the driver's performance presented in aggressive driving, this systematic review screens 2412 pieces of relevant literature, selects and synthesizes 31 reports with 34 primary studies that investigated the driver's control performance among the general driver population in four-wheeled passenger vehicles and published with full text in English. These 34 selected studies involved 1731 participants in total. By examining the selected 34 studies, the measures relating to vehicle speed (e.g., mean speed, n = 22), lateral control (e.g., lane deviation, n = 17) and driving errors (e.g., violation of traffic rules, n = 12) were reported most frequently with a significant difference observed between aggressive driving and driving in the control group. The result of the meta-analysis indicates that the aggressive driving behaviour would have 1) a significantly faster speed than the behaviour in the control group with an increase of 5.32 km/h (95% confidence interval, [3.27, 7.37] km/h) based on 8 studies with 639 participants in total; 2) 2.51 times more driving errors (95% confidence interval, [1.32, 3.71] times) than the behaviour in the control group, based on 5 studies with 136 participants in total. This finding can be used to support the identification and quantification of aggressive driving behaviour, which could form the basis of an in-vehicle aggressive driving monitoring system.

Exploring the stop sign running at all-way stop-controlled intersections with the SHRP2 naturalistic driving data

INTRODUCTION

All-way stop control (AWSC) has been widely used at unsignalized intersections in the United States for its safety effects. However, many drivers do not make a complete stop before stop signs in practice (i.e., stop sign running), which presents safety concerns.

METHOD

This study explores driver behaviors at AWSC intersections with the SHRP2 naturalistic driving data.

RESULTS

First, it is found that the full-stop rate is only 20.2% at AWSC intersections. Then, the study quantitatively analyzes what factors might influence the stop sign running decisions at AWSC intersections, where driver, vehicle, intersection geometry, maneuver, and environmental features are taken into account. In addition, considering the possible unobserved heterogeneities across drivers and intersections, a logistic regression model with both driver and intersection random effects is adopted. The results show that young and older drivers are less likely to fully stop, but there is no gender difference found. SUVs and vans are less likely to fully stop, drivers are less likely to fully stop at 3-leg intersections, and drivers are more likely to fully stop in daytime and weekdays. In terms of maneuvers, left-turn traversals are more likely to make a complete stop. In addition, both the driver and intersection random effects are found to be significant, vary greatly by individuals, and can be used to identify the few but critical high-risk drivers/intersections.

PRACTICAL APPLICATIONS

The findings are expected to provide new insights for transportation agencies to formulate effective measures to deter stop sign running.

Identification of Contributing Factors for Driver’s Perceptual Bias of Aggressive Driving in China

Aggressive driving is common across the world. While most aggressive driving is conscious, some aggressive driving behavior may be unconscious on part of motor vehicle drivers. Perceptual bias of aggressive driving behavior is one of the main causes of traffic accidents. This paper focuses on identifying impact factors related to aggressive driving perceptual bias. Questionnaire data from 690 drivers, collected from a drivers’ retraining course administered by the Traffic Management Bureau in Nanjing, China, were used to collect drivers’ socioeconomic characteristics, personality traits, and external environment data. Actual penalty points were considered as an objective indicator and Gaussian mixture model (GMM) was used to cluster an objective indicator into different levels. The driving anger expression (DAX) was used to measure drivers’ self-assessment of aggressive driving behavior and then to identify perceptual biases. Then a binary logistic model was estimated to explore the influence of different factors on drivers’ perceptual bias of aggressive driving behavior. Results showed that bus drivers were less likely to have perceptual bias of aggressive driving behavior. Truck drivers, drivers with an extraversion characteristic, and drivers who have dissatisfaction with road infrastructure and actual work were likely to have a perceptual bias. The findings are potentially beneficial for proposing targeted countermeasures to identify dangerous drivers and improve drivers’ safety awareness.

Driving anger and factors related to aggressive driving among Serbian drivers

Objective: Driving anger has been found to be a motivational determinant of risky and aggressive driving. The study reported in this article focused on research questions concerning the conceptualization of driving anger and relationships between driving anger and aggressive driving.Methods: In a cross-sectional survey study, 1,020 regular Serbian drivers completed a web-based online questionnaire. Exploratory Factor Analysis and Confirmatory Factor Analysis were used to assess the factor structure and psychometric properties of the Driving Anger Scale.Results: The results showed that the adapted DAS was a valid and reliable instrument divided into five subscales such as discourteous behavior, illegal behavior, slow driving, hostile gestures and traffic obstructions. The robustness of the five-factor model obtained from the EFA was confirmed by the CFA. The study provided evidence supporting the predictive validity of the adapted DAS and revealed that the dimensions of driving anger are differently associated with prosocial and aggressive driving behaviors.Conclusions: The study supports the adapted DAS validity and produces evidence that driving anger is associated with driving outcomes.