Factors determining speed management during distracted driving (WhatsApp messaging)

Self-Regulation of Driving Behavior Under the Influence of Cannabis: The Role of Driving Complexity and Driver Vision

OBJECTIVE

This study analyzed the self-regulation behaviors of drivers under the influence of cannabis and its relationship with road complexity and some driver traits, including visual deterioration.

BACKGROUND

Cannabis is the illicit drug most often detected in drivers; its use results in significant negative effects in terms of visual function. Self-regulation behaviors involve the mechanisms used by drivers to maintain or reduce the risk resulting from different circumstances or the driving environment.

METHODS

Thirty-one young, occasional cannabis users were assessed both in a baseline session and after smoking cannabis. We evaluated the visual function (visual acuity and contrast sensitivity) and driver self-regulation variables of both longitudinal and lateral control as the speed adaptation and standard deviation of lateral position (SDLP).

RESULTS

Visual function was significantly impaired after cannabis use. Recreational cannabis use did not result in self-regulation, although some road features such as curved roads did determine self-regulation. Male participants adopted mean faster driving speeds with respect to the speed limit. Driver age also determined better lateral control with lower SDLPs. In addition, visual impairment resulting from cannabis use (contrast sensitivity) was linked with self-regulation by changes in longitudinal and lateral control.

CONCLUSION

Contrast sensitivity could be a good indicator of individual visual status to help determine how drivers self-regulate their driving both in normal conditions and while under the influence of cannabis.

APPLICATION

The findings provide new insights about driver self-regulation under cannabis effects and are useful for policy making and awareness campaigns.

A hierarchical cluster analysis of young drivers based on their perceived risk and frequency of texting while driving

INTRODUCTION

The present study attempted to provide a proof-of-concept of usefulness of cluster analysis for identifying distinct and practically meaningful subgroups of drivers who differed in their perceived risk and frequency of texting while driving (TWD).

METHOD

Using a hierarchical cluster analysis, which involves sequential steps in which individual cases are merged together one at a time based on their similarities, the study first attempted to identify distinct subgroups of drivers who differed in their perceived risk and frequency of TWD. To further evaluate the meaningfulness of the subgroups identified, the subgroups were compared in terms of levels of trait impulsivity and impulsive decision making for each gender.

RESULTS

The study identified the following three distinct subgroups: (a) drivers who perceive TWD as risky but frequently engage in TWD; (b) drivers who perceive TWD as risky and infrequently engage in TWD; and (c) drivers who perceive TWD as not so risky and frequently engage in TWD. The subgroup of male, but not female, drivers who perceive TWD as risky but frequently engage in TWD showed significantly higher levels of trait impulsivity, but not impulsive decision making, than the other two subgroups.

DISCUSSION

This is the first demonstration that drivers who frequently engage in TWD can be categorized into two distinct subgroups that differ in terms of the perceived risk of TWD.

PRACTICAL APPLICATIONS

For drivers who perceived TWD as risky yet frequently engage in TWD, the present study suggests that different intervention strategies may be needed for each gender.

Effect of peripheral refractive errors on driving performance

The effect of peripheral refractive errors on driving while performing secondary tasks at 40° of eccentricity was studied in thirty-one young drivers. They drove a driving simulator under 7 different induced peripheral refractive errors (baseline (0D), spherical lenses of +/- 2D, +/- 4D and cylindrical lenses of +2D and +4D). Peripheral visual acuity and contrast sensitivity were also evaluated at 40°. Driving performance was significantly impaired by the addition of myopic defocus (4D) and astigmatism (4D). Worse driving significantly correlated with worse contrast sensitivity for the route in general, but also with worse visual acuity when participants interacted with the secondary task. Induced peripheral refractive errors may negatively impact driving when performing secondary tasks.

Speed management across road environments of varying complexities and self-regulation behaviors in drivers with cataract

Evidence suggests that drivers with cataract self-regulate their driving, but there is a lack of objective information. This study compared speed behavior in older drivers with and without cataract and how the parameter is influenced by road traffic complexity and driver characteristics. The study included 15 drivers with cataract and a control group of 20 drivers. Visual status was assessed using visual acuity, contrast sensitivity, and intraocular straylight. Speed management was studied using a driving simulator. Driving difficulty and self-regulation patterns were evaluated by means of the Driver Habits Questionnaire (DHQ). The cataract group showed a significant decrease in visual function in all the parameters evaluated (p < 0.05). These drivers tended to drive at lower speeds than the control group. Road characteristics, gender, and intraocular straylight in the better eye were identified as significant predictors of speed management. Drivers with cataract experience greater driving difficulty, particularly when driving at night (p < 0.05). Drivers with cataract reduce their driving speed more than older drivers without visual impairment. The straylight parameter may be a good indicator of each driver's subjective perception of their own visual ability to drive. This work helps shed light on the mechanisms through which age-related visual impairment influences driving behavior.

Social Psychology and the Willingness of Different Citizens to Participate in a Car Lottery

To investigate citizens’ participation behavior in the lottery under the influence of the license plate lottery policy (LPLP) and to guide them to participate in the lottery rationally, this paper, based on social psychology and combined with the theory of planned behavior, divides citizens into citizens with cars in their households and citizens without cars in their households. This study then separately constructs structural equation models, sets perceived car necessity (PCN), perceived behavioral control (PBC), attitude toward car ownership (ATT), and subjective norms (SN), respectively. These four psychological latent variables were used to analyze the participation behavior of different categories of citizens in the car lottery from the perspective of psychological factors. Our empirical study found that there are significant differences in age and the number of people living together. The mechanism of their intention to participate in the car lottery and the psychological factors are different. The psychological factors affecting the intention of people with a car and people without a car to participate in the car lottery are SN > ATT > PCN > PBC and ATT > SN > PBC, respectively. Our research results can help to identify the internal factors and mechanisms that influence citizens’ intention to participate in the car lottery and help government administrators to optimize the LPLP.

Aggressive Driving Behaviours in Cannabis Users. The Influence of Consumer Characteristics

This study analysed dangerous driving behaviours in twenty young occasional cannabis users through objective and self-reported data, studying the relationship between the two aspects. Visual function was assessed in a baseline session and after smoking cannabis, as well as speed-related behaviour in a driving simulator. The participants responded to questionnaires on sociodemographic factors, their consumption profile, and the incidence of dangerous behaviours (Dula Dangerous Driving Index; DDDI). After cannabis use, the results revealed a significant deterioration in visual function. In terms of speed management, they showed significantly greater acceleration force in the two different sections of the route, and they drove significantly faster. Our correlations indicate that males and heavier users display more risky speed management. Likewise, the heavier cannabis users admitted to increased dangerous driving behaviour, and an accident in the preceding year was associated with a trend towards aggressive driving behaviour according to the DDDI questionnaire. The findings of this study suggest that cannabis users adopt dangerous behaviours when driving, despite the effect this drug has on certain important functions, such as vision. The results suggest a need for awareness-raising and information campaigns.

Effects of Smoking Cannabis on Visual Function and Driving Performance. A Driving-Simulator Based Study

Cannabis is the most widely used illegal drug in the world. Limited information about the effects of cannabis on visual function is available, and more detail about the possible impact of visual effects on car driving is required. This study investigated the effects of smoking cannabis on vision and driving performance, and whether these effects are correlated. Twenty drivers and occasional users were included (mean (SE) age, 23.3 (1.0) years; five women). Vision and simulated driving performance were evaluated in a baseline session and after smoking cannabis. Under the influence of cannabis, certain visual functions such as visual acuity (p < 0.001), contrast sensitivity (p = 0.004) and stereoacuity (far, p < 0.001; near, p = 0.013) worsened. In addition, there was an overall deterioration of driving performance, with the task of keeping the vehicle in the lane proving more difficult (p < 0.05). A correlation analysis showed significant associations between driving performance and visual function. Thus, the strongest correlations were found between the distance driven onto the shoulder and stereoacuity, for near (ρ = 0.504; p = 0.001) and far distances (ρ = 0.408; p = 0.011). This study provides the first evidence to show that the visual effects of cannabis could impact driving performance, compromising driving safety. The results indicate that information and awareness campaigns are essential for reducing the incidence of driving under the influence of cannabis.