Modeling and prediction of driver preparations for making a right turn based on vehicle velocity and traffic conditions while approaching an intersection

This paper focuses on modeling and predicting the influence of a vehicle’s velocity and the relative position between a driver’s vehicle and a vehicle to the front or rear on the onset of driver preparations for making a right turn at an intersection. Repeated experiments were carried out on a public road to measure driver preparations, including releasing the accelerator pedal, moving the right foot to cover the brake pedal, and activating the turn signal, as well as to record vehicle velocity and the relative distances to the leading and following vehicles. Structural equation modeling was applied to estimate these relationships quantitatively. Two separate latent variables accounting for the interaction between the driver’s vehicle and leading or following vehicles, and the onset point where driving behavior changes from straight mode to preparation mode before a right turn, were introduced in the specification of the structural equation model. The model estimates and testing indicate that the proposed structural equation model represents well the relationship hypothesized by observational analysis: that the vehicle velocity and the traffic conditions surrounding the driver’s vehicle strongly influence the driver’s deceleration and more weakly influenced turn signal activation. The proposed structural equation model contributes to the prediction of the onset locations of covering the brake pedal and activating the turn signal based on the vehicle velocity and the relative distances to the front and rear vehicles when the accelerator pedal is released. The prediction accuracy is high compared with predictions in which the vehicle velocity and the headway or rear distances are not taken into account or predictions using a single regression model with one independent variable, namely driving speed. Finally, a possible new addition to in-vehicle navigation systems that detects unusual driver behavior by predicting the driver’s preparatory maneuvers is discussed.     

The experience of road environments under two lighting and traffic conditions: Application of a road environment construct list

The aim of this study is to find out whether the different accident rates on two roads may be explained by drivers' different appreciations of these roads. Therefore a rating scale specially developed for the evaluation of drivers' experience of the road environment was used. The study is based on the assumption that experience of the road environment is an important factor in driving behaviour. An experiment was carried out in which two roads were compared in daylight and darkness, with and without traffic. The roads were presented on films. Subjects' evaluation scores appeared to be founded on three factors, which explained 66.8 per cent of the variance. The factors were named ‘hedonic value’, ‘activational value’ and ‘perceptual variation’. Composite scores were constructed from the rating scale scores for each factor, per road, and condition. This revealed that the two roads differed on all three factors. Ambient lighting and traffic conditions also influenced the values of the factors and some interactions were found. The range of scores for one road was greater than for the other. The road that ranked lowest on activational level and perceptual variation, especially during daylight conditions with no traffic, was ranked highest on hedonic value. This combination of conditions and experiences could explain the higher rate of ‘incomprehensible’ single vehicle accidents on that road compared with the other.     

Influence of consultation on ethical decision making: an analogue study

Participants (62 students from 6 doctoral programs in professional psychology) were given 3 ethical dilemmas, asked to generate their own solutions, and asked to make judgments about a number of provided alternatives. Students were asked either to make decisions after seeking consultation or to make decisions independently of consultation. There were few significant between-group differences along a number of dimensions including participants' ratings of acceptability of provided alternatives and levels of certainty, justification, and satisfaction with personally generated solutions. For one of the vignettes, individuals using consultation, when compared with the control group, were significantly more likely to prefer their own solution to that of provided alternatives. The study was viewed as a needed first step in investigating a cherished assumption in clinical practice.     

Approaching intersections: Gaze behavior of drivers depending on traffic,intersection type,driving maneuver,and secondary task involvement

Urban intersections are hotspots for crashes because they provide a location for several traffic streams and types of road users to cross. A main cause of crashes is the misinformation of drivers as they fail to sense relevant visual information. We aimed to analyze the gaze behavior of car drivers in a variety of intersection scenarios, bringing together the partial findings of previous research, and examine the interdependencies of the contributing factors to provide a database for driver modeling. In a driving simulator study with 59 participants, we varied intersection scenarios regarding drivers’ right of way (yield sign, green traffic light), intersection type (T junction, X intersection), surrounding traffic (none, irrelevant, relevant), and intended driving maneuver (left turn, right turn, going straight). A total of 25 intersection scenarios were presented in a within-subjects design to a control group and a group with a cognitive load task (counting back in numbers of two). Fixations were coded regarding defined areas of interest in the field of view and separated according to three segments of the intersection approach: 75–50 m, 50–25 m, and 25–0 m before entering the intersection. The results show that the effect of surrounding traffic, secondary task engagement, and the intended driving maneuver changed dramatically depending on the right of way of the driver. Surrounding traffic primarily affected gaze behavior in scenarios of ceding the right of way close to the intersection entry. The cognitive load task increased fixations on the road center especially in situations where the driver had the right of way, but less in situations of ceding the right of way. Interactions with the type of intersection were only apparent for different driving maneuvers. This study provides a detailed and comprehensive picture of drivers’ attentional processes when approaching intersections which is relevant for understanding and modeling of driver behavior in urban traffic.     

Sandstorm animations on rural expressways: The impact of variable message sign strategies on driver behavior in low visibility conditions

Problem: Evolving sandstorms on rural expressways in desert countries impair drivers' contrast vision and increase the risk of serious crashes due to delayed speed adjustments. Intelligent Transport Systems (ITS) such as Variable Message Signs (VMS) conveying warnings can be activated to address drivers’ speed adaptation before entering a low visibility zone. To improve drivers’ understanding of the hazard, a sandstorm animation visualizing turbulent sand and its consequences was designed and compared with a general warning pictogram, which is applied if no specific weather pictogram is available. Moreover, minimum warning distances of the VMS to the low visibility zone were tested (e.g., 300 m or 500 m).MethodSixty-three participants from the State of Qatar drove in a driving simulator through clear, transition, and low visibility conditions on a rural expressway. A repeated analysis of variances was conducted to examine the impact of the two on-road warning displays on driving behavior.ResultsThe results showed that the sandstorm animation was similarly effective as a generic warning pictogram in reducing driving speeds before entering the transition and low visibility zone, irrespective of being displayed 500 m or 300 m away. However, the sandstorm animation resulted in consistent similar speed reductions within the low visibility zone, whereas the generic warning pictogram did either perform better or worse after several encounters with a sandstorm. Drivers did strongly agree that the animation is clearly referring to the issue of low visibility, which can be beneficial for recurring low visibility conditions.Practical applications: 1.) Displaying a sandstorm animation is beneficial for rural expressway sections with recurring degrading visibility and low traffic densities, whereas a warning pictogram can be more effective in speed reductions if drivers expect additional traffic hazards. 2.) Roadway authorities have the flexibility to activate a VMS sandstorm warning even for minimum warning distances.     

Investigating the impact of a novel active gap metering signalization strategy on driver behavior at highway merging sections

A safe headway to the lead vehicle is important to reduce conflicts with merging vehicles from highway on-ramps. Previous research has outlined the advantage of gap metering strategies to yield sufficient space to merging vehicles and improve highway capacity during peak hours. However, prevailing gap metering systems fail to indicate the minimum required gap and leave it to the drivers’ judgment to adjust their headway. This paper proposes a new Active Gap Metering (AGM) signalization that helps outer lane drivers to adjust their headway to the lead vehicle when approaching highway ramps with incoming vehicles. This AGM signalization represents a combination of pavement markings and an innovative Variable Message Sign (VMS). The AGM system was tested alone and in combination with additional variable speed limits (VSL) in distinct environments of the Doha Expressway in the State of Qatar using a driving simulator. The driving behavior of 64 drivers was analyzed using repeated-measures ANOVA. The results showed that the AGM effectively influenced the drivers’ behavior on the right stream lane. Drivers did gradually increase the distance to the lead vehicle, which resulted in optimal headways to merging on-ramp vehicles. Most importantly, the minimum time-to-collision (TTC_min) to the merging vehicle was increased by an additional 1–1.5 s as compared to no treatment. The proposed AGM signalization can, therefore, be considered by policymakers to influence drivers’ headways at critical merging sections.     

Familiarity breeds contempt for the road ahead: The real-world effects of route repetition on visual attention in an expert driver

The majority of journeys by car take place on familiar roads, with many routes being driven time and time again. This familiarity has been linked to mind wandering and reduced attention to specific elements of the visual scene (e.g. speed signs). The current study presents on-road eye tracking data from a driving instructor who drove the same route 28 times, incorporating two types of suburban roads, dual and multi-lane carriageways, and a country road. Data reveal a significant positive correlation between the number of times the same route is navigated and off-road dwell time across all five road sections. In addition, route familiarity was associated with decreasing dwell time on safety-relevant aspects of the road ahead in four out of the five sections. These data suggest that route familiarity can lead to undesirable changes in visual attention on real roads, even for expert drivers under observation.     

Pedestrian behaviors at and perceptions towards various pedestrian facilities: an examination based on observation and survey data

This paper presents findings from an observational study of pedestrian behaviors at various urban crosswalks and a pedestrian user survey which sought pedestrian perceptions toward various pedestrian facilities in a divided urban boulevard located next to a large university campus, Michigan State University, East Lansing, MI, USA. Such facilities included signalized and unsignalized intersection crosswalks, unsignalized marked and non-striped midblock crosswalks, physical barriers (vegetation and two-foot high concrete wall), midblock crosswalk shelters, colored paving (red brick pavement) at medians and curbs, and pedestrian warning signs at midblock crossing locations, messaging “cross only when traffic clears.” Pedestrian behavior data were obtained from the reduction of video images of pedestrian movements recorded throughout the study site. Pedestrian perceptions information was obtained through a user survey completed by pedestrians using the study site. It was found that unsignalized midblock crosswalks were the treatment of preference to pedestrians (83% reported a preference to cross) and also showed high crossing compliance rate of pedestrians (71.2%). It was also evident that the crosswalk location, relative to the origin and destination of the pedestrian, was the most influential decision factor for pedestrians deciding to cross at a designated location (90% said so). Proper traffic control can further encourage pedestrian crossings at designated locations since the effect of the availability of pedestrian signal to influence pedestrians’ decisions to cross at a specific location was quite high (74% said so). Moreover, vegetation and concrete barriers influenced the decision to cross of a significant number of pedestrians surveyed (65%). It is expected that the findings from this study will help traffic engineers, urban planners and policy makers understand pedestrian behaviors and attitudes at/towards pedestrian crosswalks.     

The effect of cognitive behavior therapy on decision making in adolescents who self-harm: a pilot study

Research shows poor decision making in adolescents who self-harm and a positive correlation between decision-making abilities and duration since last self-harm episode. This exploratory study investigated whether decision making in self-harming adolescents could be improved through treatment with a novel cognitive behavior therapy (CBT). It also investigated whether improvement in decision making following treatment was linked to self-harm cessation. Adolescent self-harmers receiving CBT (n = 24) or no treatment (n = 9) and healthy controls (n = 22) were longitudinally compared on the Iowa gambling task (IGT). Significant IGT improvements were only observed for adolescents who self-harm following CBT. CBT may benefit adolescent self-harmers and generate decision-making improvements.     

Bullying at work: a discussion of definitions and prevalence, based on an empirical study

The past 15 years have witnessed a growing interest in studies of bullying in the area of work and organizational psychology, but the results of research on this topic seem to indicate very wide variations in the prevalence of bullying. The range of differences may be primarily due to the utilization of different categories and operationalizations of the concept. The aim of this study is to discuss definitions and delimitations of the phenomenon known as bullying, and to demonstrate empirically how the prevalence of bullying can be determined by the way in which it is defined and delimited. On the background of a discussion of some current definitions of bullying and a survey of some central research results on its rate of occurrence, this study presents the results of a study of 3,024 public-sector employees. The results showed that 1.0% of the sample reported that they had been bullied weekly during the previous six months, while 4.7% reported themselves as having been exposed to acts of bullying with the same frequency and for the same period of time. If we change the criteria from "weekly" to "2-3 times a month" the prevalences rise to 3.7% and 26.9%. Based on observations of bullying the prevalence is 3.3%. The results are discussed with reference to other studies that are comparable in terms of delimitations and rates of occurrence and it is concluded that the prevalence is at the same level as these.     

Analysis of clustered data in community psychology: With an example from a worksite smoking cessation project

Although it is common in community psychology research to have data at both the community, or cluster, and individual level, the analysis of such clustered data often presents difficulties for many researchers. Since the individuals within the cluster cannot be assumed to be independent, the use of many traditional statistical techniques that assumes independence of observations is problematic. Further, there is often interest in assessing the degree of dependence in the data resulting from the clustering of individuals within communities. In this paper, a random-effects regression model is described for analysis of clustered data. Unlike ordinary regression analysis of clustered data, random-effects regression models do not assume that each observation is independent, but do assume data within clusters are dependent to some degree. The degree of this dependency is estimated along with estimates of the usual model parameters, thus adjusting these effects for the dependency resulting from the clustering of the data. Models are described for both continuous and dichotomous outcome variables, and available statistical software for these models is discussed. An analysis of a data set where individuals are clustered within firms is used to illustrate fetatures of random-effects regression analysis, relative to both individual-level analysis which ignores the clustering of the data, and cluster-level analysis which aggregates the individual data. Preparation of this article was supported by National Heart, Lung, and Blood Institute Grant R18 HL42987-01A1, National Institutes of Mental Health Grant MH44826-01A2, and University of Illinois at Chicago Prevention Research Center Developmental Project CDC Grant R48/CCR505025.     

Peer influences on risk behavior: an analysis of the effects of a close friend

Cross-sectional research suggests that peer influence has a moderate to strong impact on adolescent risk behavior. Such estimates may be inflated owing to third-variable confounds representing either friendship selection effects or the operation of parallel events. Approximately 1,700 peer dyads in Grades 7 to 11 were studied over a 1-year period to estimate the influence of closest friends on sexual activity and binge drinking. Analyses suggested that peer influence was small but reliable when both selection effects and parallel events were taken into account. Peer influence varied as a function of individual-peer similarity and maternal relations but not in accord with other theoretical predictions. It is suggested that the magnitude of peer effects in previous research may be overestimated in many contexts.     

Measuring social influence of a senior midwife on decision‐making in maternity care: an experimental study

The document Changing Childbirth produced by the Department of Health (1993) requests provision of more choice, continuity and control for women during pregnancy and childbirth. In this context this study considers whether midwives'decisions are influenced by a senior midwife. A simple, valid and reliable scale—the Social Influence Scale for Midwifery (SIS‐M)—was devised to measure and score midwives' private anonymous responses to 10 clinical decisions. The SIS‐M was initially administered as a self‐completed postal survey by 209 midwives. Following a 9‐month time gap, a stratified sample of 60 (20 E, F, G grade midwives) were invited for interview in which a senior midwife attempted to influence SIS‐M responses in a conformist direction. Overall, a 3 × 2 (E, F, G grade midwives x private and interview SIS‐M scores) analysis of variance (ANOVA) revealed midwives were significantly more conformist when influenced by a senior midwife, in comparison to private anonymous responses. No significant interaction between groups was found. These findings indicate that there is influence of a senior midwife on clinical decisions that should be woman‐centred, according to Changing Childbirth (1993). The implication is that this influence may remove choice from women. Copyright © 2005 John Wiley & Sons, Ltd.     

Investigating the effects of Rectangular Rapid Flash Beacons on pedestrian behavior and driver yielding on 25 mph streets: A quasi-experimental field study on a university campus

Rectangular Rapid-Flash Beacons (RRFBs) are safety measures that have become popular in recent years in the USA. Such equipment has demonstrated effectiveness in reducing vehicle speed and conflicts among road users, and increasing drivers’ yielding to pedestrians. However, RRFB effects on pedestrian behaviors are less well documented, and perhaps could produce contraindicated effects in crossing behavior. Specifically, RRFBs may give pedestrians a feeling of protection and induce them to more risk-taking when crossing the road. The current study was designed to investigate drivers and pedestrians’ reactions to a RRFB system installed at a university campus located in Virginia, USA. We deployed (a) field observation, using a multiple pretest/posttest non-equivalent control group quasi-experiment design and (b) interviews of students throughout the project’s multiple time periods. In total, 2454 pedestrians and 1312 drivers were observed and 265 students were interviewed. RRFB installations did not distinguish driver yielding likelihood between sites with or without RRFBs. However, driver yielding overall increased linearly over the five rounds of the study. Whether this was the result of the general presence of RRFBs on campus from the third round to the end of the fifth round is unknown. There is evidence from person interviews that students perceived increased safety for pedestrians over time. Being a RRFB chosen site or actual activation of the RRFBs did not have a significant relationship with pedestrian looking behavior either. The potential consequences of these results as well as the context of RRFB use on a university campus and generally low-speed roads are discussed.     

Perceptions of psychological researchers and clinicians: a questionnaire based on empirical data and theory.

Clinical and research psychologists continue to be regarded stereotypically even by 187 students currently anticipating careers in psychology and closely related fields. This article gives data for 10 issues on which clinicians and researchers are perceived to differ. Specifically, a 10-item questionnaire is described which allows such stereotypes to be further explored or explained.     

Analysis and visualization of complex psychophysiological data: Coordinated use of multiple applications on a microcomputer

Personal computers have become ubiquitous for data analysis and visualization. Complex analyses and visualizations of large data sets prove challenging for microcomputer environments and highlight a tradeoff between customized programming to enhance specificity and processing speed and the use of commercially available software packages. We frame this choice in terms of a continuum that exists from low-level programming languages to higher-level languages, and beyond this to object-oriented programming environments and other advanced software products; we argue that there is no sharp conceptual distinction between programming and not programming. In this light, we discuss the pros and cons of using several commercial software packages in concert on a single platform to facilitate complex research tasks and discuss the implications of this choice for innovative research.