Effectiveness of the compensatory strategy adopted by older drivers: Difference between professional and non-professional drivers

It has been a controversial issue for the effect of ageing population on driving safety. Apparently, drivers’ physiological and cognitive performances deteriorate with age. However, older drivers may compensate for the elevated risk by adjusting their behaviors, known as compensatory strategy. Despite the extensive research on this topic, the compensatory strategy of older professional drivers is not well understood since many studies focused on the differences in compensatory behavior between older and young drivers. Professional drivers tend to be more skillful and able to cope with the unfavorable driving environments, thus presenting a higher capability to mitigate the risk. This study attempts to examine the compensatory behavior and its safety effect amongst older professional drivers, as compared to those of older non-professional drivers, using the driving simulator approach. In the driving simulator experiment, participants were asked to follow a leading vehicle for one hour, and two sudden brake events were presented. 41 (mid-aged and older) drivers completed the driving tests. Each participant was required to complete a car-following test, either under high or low traffic flow conditions. Performance indicators include driving capability (i.e. lateral control, longitudinal control, and brake reaction time) and compensatory behavior (i.e. average speed, and time headway). Additionally, two modified traffic conflict measures: time exposed time-to-collision (TET) and time integrated time-to-collision (TIT) are applied to indicate the traffic conflict risk. The random parameter Tobit models were estimated to measure the association between conflict risk and driver attributes, and random intercept models were used to assess other driving performance indicators. Results show that despite the impaired lateral control performance and longer brake reaction time of older drivers, the likelihood of severe traffic conflict of older drivers is lower than that of mid-aged drivers. Furthermore, though both older professional and older non-professional drivers adopted longer time headway, the reduction in the risk of severe traffic conflict is more profound among the older professional drivers. Such findings suggest that older professional drivers are more capable of mitigating the possible collision risk by adopting the compensatory strategy, as compared to older non-professional drivers. This justifies the existence of compound effect by the compensatory strategy of older driver and better driving skills of professional driver. This research provides useful insights into driver training and management strategies for employers, as older drivers would become a major cohort in the transportation industry.     

Attitudes,norms and driving behaviour: A comparison of young drivers in South Africa and Sweden

Culture is increasingly recognised among traffic psychologists to be a factor influencing driving behaviour. This study examines whether a cultural background characterised by rapid social change and high levels of violence and aggression, as in the South African context, has any discernible influences on driving standards or the behaviour of individual drivers. The experiences and attitudes of young drivers in South Africa are compared with a group of young drivers from Sweden, a country whose society has exhibited high levels of stability and where road user behaviour is renowned for its restraint and compliance with regulations.The two cohorts provide information about their exposure to traffic injuries, their attitudes to other drivers and to a range of traffic offences, and to the types of behaviour they personally engage in. Among the South African respondents the notion of a declining standard of driving emerges very clearly, and specific new norms of driving are identified. Such norms are explained to be a consequence of new social values or challenges inherent within contemporary South African society.     

Effects of personality on driving behaviors among professional truck drivers: The mediating effect of safety climate

Introduction: The number of traffic accidents involving truck drivers remains high, and strategies to eliminate the probability of such accidents have been proposed, among which enhancing the safety climate has attracted much interest. The main purpose of the current study was to validate the Chinese version of the safety climate scale for truck drivers and apply it to investigate the mediating effect of safety climate between truck driver personality and driving behavior. Method: A total of 389 male truck drivers completed the Big Five Inventory, the Chinese version of the trucking safety climate scale, the driver behavior questionnaire and the positive driver behavior scale. Results: The reliability and validity of the Chinese version of the organization-level safety climate scale and the group-level safety climate scale were confirmed through factor analysis. More importantly, a path analysis revealed that the organization-level safety climate mediated the effects of agreeableness and neuroticism on aggressive violations, ordinary violations and lapses, while the group-level safety climate mediated the influences of agreeableness, neuroticism and openness on positive behavior and all four kinds of aberrant driving behaviors. Conclusions: This study introduced the trucking safety climate scale into China and stressed the significance of improving both the organizational and the group levels of safety climate to reduce accidents involving professional truck drivers. Practical Applications: First, the adapted safety climate scale for Chinese truck drivers contributes to further investigating the role that safety climate plays in the safety problem of truck drivers in China. Moreover, the critical impacts of both levels of the trucking safety climate serve as reminders for relevant companies to not only pay attention to establishing an organization-level safety climate but also invest more effort into promoting the group-level safety climate.     

Driver behaviour and traffic accident involvement among professional urban bus drivers in China

The present research aimed to investigate specific behaviors of professional urban bus drivers in China with the revised Driver Behavior Questionnaire (DBQ), and to define the relationships among various driving behaviors (errors, positives, inattention errors, violations), background information (age, years of driving experience, mobility, etc.), self-assessment, and traffic accident. To achieve such goals, the present research designed a four-dimensional DBQ with 20 items for professional urban bus drivers in China. The KMO coefficient of the whole scale was 0.835, and Bartlett’s test was statistically significant (p < 0.000), which demonstrated strong validity of the scale and should be suitable for factor analysis. The four loading factors accounted for 58.991%. In addition, the reliability and effectiveness of the present 20-item scales were measured. The coefficient of internal consistency-Cronbach’s alpha coefficient was 0.881 and the Cronbach’s Alpha Based on Standardized Items was 0.911. This showed that driving behavior scale of professional bus drivers in China was of high reliability and validity. The analysis showed that among the four factors, positive driving behaviors were significantly associated with errors, inattention errors and violations, respectively. Errors, inattention errors and violations correlated positively with each other. This verified that the correlation coefficient of each factor was medium and high, which indicated that the scale had good difference validity. The test content of the total scale was also highly consistent with the test content of each factor, which indicated that the revised scale had good standard related validity. According to the accident prediction model, the variables that significantly affected the occurrence of traffic accidents were daily driving time, positive driving behavior, SE2 (Driving safety), SE3 (Aberrant driver behaviors). The results showed that professional bus drivers often working overtime were most likely to have accidents. The probability of traffic accidents decreased by 53% for every unit of positive driving behavior frequency of professional bus drivers. The more they felt that they had the tendency of aberrant driving behavior, the more likely they were to have traffic accidents. To summary, the present research contributed to validating and improving the DBQ for professional urban drivers in China.     

The differences in hazard response time and driving styles of violation-involved and violation-free taxi drivers

The present study aimed to investigate the relationships between taxi drivers’ traffic violations in past driving and two domains: driving skill (hazard perception skill) and driving style. Five hundred and fifty taxi drivers aged 25 – 59 were recruited to finish a video-based hazard perception test and the Chinese version of the Multidimensional Driving Style Inventory (MDSI). The relationships between hazard response time, driving style and traffic violations were examined, and the differences in hazard response times and driving styles of violation-involved drivers (n = 220) and violation-free drivers (n = 330) were compared. The results showed that taxi drivers’ traffic violations are closely related to their driving styles and hazard response time. Violation-involved drivers scored significantly higher in hazard response time and maladaptive driving styles (i.e., anxious, risky and angry styles) and lower in careful driving style than violation-free drivers. More importantly, drivers’ hazard response time and driving styles can effectively predict their violation involvement in the last 12 months with an overall classification accuracy of 66.4%. The findings provide evidence for the usefulness of video-based hazard perception tests and the MDSI in taxi driver testing and training.     

Cognitive function and young drivers: The relationship between driving,attitudes, personality and cognition

Young drivers (aged 17–25 years) are the highest risk age group for driving crashes and are over-represented in car crash statistics in Australia. A relationship between cognitive functioning and driving in older drivers (60 years and older) has been consistently supported in previous literature, however, this relationship has been neglected in research regarding younger drivers. The role of cognitive functioning in young people’s driving was investigated both independently and within a current model of younger peoples driving performance. With young drivers as participants, driving behaviour, attitudes, personality and cognitive functioning were tested and driving performance was operationalised through two measures on a driving simulator, speeding and lane deviations. Cognitive functioning was found to contribute to driving behaviour, along with driving attitudes and personality traits, in accounting for young people’s driving performance. The young drivers who performed better on cognitive functioning tasks engaged in less speeding behaviour and less lane deviation on the driving simulator than those who performed worse on these tasks. This result was found independent of the role of driving behaviour, driving attitudes and personality traits, accounting for unique variance in driving ability.     

Driving performance while using a mobile phone: A simulation study of Greek professional drivers

PurposeThe current study aims to assess the driving performance of professional drivers while using a mobile phone.Material and methodsA sample of 50 male professional drivers participated in the study. The sample was drawn conveniently from the professional drivers’ registries and the main taxi ranks. The inclusion criteria were: (a) age above 18 years, (b) possession of a driving license, (c) sufficient reading, writing, and communicating skills, (d) informed consent prior to participation. Laboratory tests were conducted using the VS500M driving simulator manufactured by Virage Simulation Inc. The intervention involved different tasks/assignments: (a) driving without using a mobile phone (Control time), (b) driving while having a conversation on the mobile phone, (Task_1), (c) driving while reading out loud text messages (Task_2) and, (d) driving while texting (Task_3). Differences in the driving performance between the control time and the time with assignments, were examined. The participants were evaluated on the followings outcome measures: (a) variation of the steering position per second, (b) following distance per second, (c) variation of the lateral lane position per second, and (d) sum of squared acceleration per second.ResultsThe analysis indicated that “variation of the steering position per second” was significantly affected by “text-message reading” [t(50) = −5.443; p < 0.0001] and “texting” [t(50) = −5.442; p < 0.0001]. A significant main effect was observed in terms of the “following distance per second” and the “variation of the lateral lane position per second” for all the three mobile phone assignments. Lastly, the “sum of squared acceleration per second” was significantly decreased during conversation on the phone [t(50) = 2.713; p = 0.009] as well as during texting [t(50) = 3.428; p = 0.001] as compared with the control time.ConclusionsThe study is among the few existing experimental studies in a country with one of the highest road fatalities in Europe but with limited evidence on road traffic behaviour. This study could guide the design of large-scale simulation studies aiming to explore the impact of mobile phone on driving behaviour.     

Driving distraction at night: The impact of cell phone use on driving behaviors among young drivers

Currently, young drivers are more likely than other drivers to use cell phones while driving at night, which has become a major cause of road crashes. However, limited attention has been given to distracted nighttime driving. Therefore, the aim of this study was to explore the interaction effect of cell phone use and time of day (daytime and nighttime) on young drivers’ car-following performance. Forty-three young drivers engaged in a driving simulator experiment with a within-subject design that included three distractions (no distraction, talking and texting on a cell phone) and two times of day. This paper applied non-parametric tests to analyze the data and obtained the following results: (1) the standard deviation of lane position (SDLP) did not significantly differ at either time of day under no distraction, but it was significantly higher at night on straight roads and large-radius curves after introducing distractions. In addition, participants drove faster and gave less headway on small-radius curves under both distractions at night; (2) texting significantly increased the SDLP, while there was less lateral variation during the talking tasks than under no distraction on simple road sections; and (3) compared with the experienced drivers, the novice drivers drove faster during the talking tasks on small-radius curves, but there was no significant difference between groups during the texting tasks. These findings provide both theoretical and practical implications for related policy makers to enhance traffic safety.     

Validation of the F-DBQ: A short (and accurate) risky driving behavior questionnaire for long-haul professional drivers

Although the Driving Behavior Questionnaire (DBQ) remains the most known tool for assessing risky road behaviors among motor vehicle drivers, recent studies have raised several concerns on the specificity of both driving task conditions and behavioral repertory of certain segments of the driving population. Among them, long-haul (cargo) professional drivers constitute one of the “intensive driving” groups for which the existing adapted behavioral research tools are still very scarce.PurposeThe aim of the present study was to test and validate the F-DBQ (or “Freight Driving Behavior Questionnaire”), a short version of the DBQ adapted to the occupational driving conditions and typical road risk behaviors of freight drivers.MethodFor this cross-sectional study, a sample of n = 982 Spanish long-haul drivers with a mean age of 48.5 years was used, responding to a questionnaire composed of measures on road risk behaviors (DBQ), fatigue (Checklist Individual Strength – CIS and Need for Recovery Scale – NFR) and job stress (Effort–Reward Imbalance questionnaire – ERI).ResultsThrough competitive Confirmatory Factor Analyses (CFA) with structural equation models, it was found that the F-DBQ has a clear dimensional structure, a fair goodness-of-fit, high factorial weights, internal consistency, convergent and discriminant validity and an improved fit to long haul drivers’ working conditions. Also, both (general and work-related) fatigue and job stress have shown to have a significant role in explaining risky road behaviors of long-haul drivers.ConclusionThe findings of this study support that an abbreviated version of the Driving Behavior Questionnaire (the F-DBQ) can be used to assess traffic violations and errors among long-haul drivers, in consideration of their specific task-related conditions (that qualitatively differ from other groups of drivers), with potential implications on the enforcement of occupational and road safety research.     

Cognitive and personality determinants of safe driving performance in professional drivers

Large truck and bus crashes still cause a high rate of fatalities and costs. Considering that the human factor plays an important role it is obvious that there is great interest in predicting safe driving performance in professional drivers, especially with new technologies emerging to assist drivers. This study uses a modern theoretical framework to assess which psychometric tests are still able to predict safe driving performance in today’s professional drivers under these new circumstances.126 male professional bus drivers completed a standardized digital test battery and three driving exercises. The test battery was used to assess reaction time, concentration, ability to gain an overview, reactive stress tolerance, logical reasoning, and safety-related personality traits. The exercises consisted of an on-road driving test, an obstacle course, and a maneuvering course.The study yielded satisfactory indicators of criterion related validity. It also showed that different tests were relevant for the prediction of safe driving performance in different driving exercises. Contrary to previous research, logical reasoning showed significant effects. The results indicate that in order to assess safe driving performance in professional drivers, a comprehensive assessment with psychometric tests should be recommended.     

Capturing the effects of texting on young drivers behaviour based on copula and Gaussian Mixture Models

This research effort aims to investigate the impact of texting on young drivers' behavior and safety based on data from driving simulator experiments, for different driving contexts, like motorways, urban and rural roads, during daytime and night, and for alternative weather conditions (‘clear sky’ and rain). The study offers a complete and comprehensive investigation of the effects of texting on driving behavior, able to provide evidence on policy-making. For the purposes of this study, a driving simulator experiment was carried out where 34 young participants drove predefined driving scenarios. Initially, multivariate copula analysis was used in order to explore statistical inferences among variables, especially since it retains a parametric specification for bivariate dependencies and allows testing of several parametric structures to characterize them. Secondly, alternative copula configurations were tested, which showed that texting and other road and environmental characteristics affect young drivers behavior and in particular more than one outcome can occur at the same time. Finally, Gaussian Mixture Modeling (GMM) was employed, demonstrating that the variables' pairs that presented the strongest correlations were lane departure and speed, as well as speed and reaction time. GMMs application showed that drivers using mobile phones who were involved in a collision presented a different driving behavior compared to the drivers who were occupied but were not involved in a collision.     

Effects of a driver assistance system with foresighted deceleration control on the driving performance of elderly and younger drivers

It is imperative to enhance the safety of elderly individuals on the roads to ensure the quality of their daily life. Near-miss incidents or accidents at blind intersections often result from a conflict between the behaviors of the driver and of other road users (pedestrians and cyclists). The failure to search for potential conflict in the context of blind intersections is a concern pertaining to road safety. The proposed assistance system performs a proactive braking intervention to achieve a referenced velocity in uncertain situations, such as one in which an unobserved pedestrian might initiate a road crossing. The proactive braking intervention attempts to manage the potential risk of crashing with respect to covert hazards. Because an automated system may impair a human’s ability to perceive and respond to hazardous situations while driving, this study was designed to examine the effects of proactive braking intervention and visual support cues on elderly and younger drivers’ ability to respond to information about potentially hazardous situations. We conducted a public-road driving experiment involving 108 elderly and younger drivers from two non-overlapping age groups. It was observed that the vehicle slowdown realized through the proactive braking intervention enabled the drivers to perform safety confirmation near blind spots and caused them to be more sensitive to and wary of potential hazards. This approach could be effective not only for elderly drivers, but also for young or inexperienced ones.     

The relations between specific measures of simulated driving ability and functional ability: New insights for assessment and training programs of older drivers

To gain new insights for driving assessment and training, this study had two objectives: (1) to investigate the relations between specific measures of older drivers’ driving ability and demographic/functional ability measures, and (2) to verify the explained variance of these relations to determine the strength of these relations. A sample of 55 older drivers (mean age 76 years) completed a set of functional ability tests as well as a driving simulator test. Results indicate that (1) each specific driving measure is related to a specific set of functional abilities, and (2) only a small proportion of the variability observed in the specific driving measures is explained by demographic variables (3–15%) and by functional abilities (7–36%). For driving assessment programs, it will be necessary to assess several functional abilities to cover the complexity of the driving task. Furthermore, an assessment program focusing solely on demographic and/or functional ability measures, will not be successful in discriminating safe from unsafe older drivers. For driving training programs, it will be necessary to focus on the right set of functional abilities given that specific driving measures are related to different functional abilities. Moreover, a training targeting functional abilities might only have marginal effects on driving ability, given the relatively low amount of driving ability variance that is explained by functional abilities.     

Keep on cruising: Changes in lifestyle and driving style among male drivers between the age of 18 and 23

Despite recent improvements in general road safety levels, young male drivers in most western countries continue to be overrepresented in road traffic accidents. Lifestyle related motivational factors are a key element in the young male driver problem. Based on 379 posted questionnaires completed by the same male drivers at the age of 18 and again at the age of 23, this study examined changes in the relationship between lifestyle and driving style over a 5 year period. A number of changes in car use, driving style and engagement in different leisure time activities were found. Cruising was related to an extrovert social life as well as problem behaviours such as drink driving. At the age of 18 cruising was a part of the normal social life of the majority of the participants. However, while most drivers reduced their level of cruising as well as related problem behaviour over time, a smaller group still showed a similar life style at the age of 23. The study confirmed the importance of lifestyle related motivational factors for driving behaviour among young drivers.     

Keep calm,pay attention,and carry on: Anxiety and consciousness mediate the effect of,mindfulness on driving performance in young drivers

Road traffic crashes are currently one of the main causes of deaths in the world and many efforts have been made to develop effective interventions to reduce them. Mindfulness has risen as a method for improving mental and physical well-being and has been hypothesized as potentially beneficial for driving performance. This has led to some commercial ventures based on such hypothesis, despite that the empirical evidence backing up them is still limited. Besides, at the moment there is not yet a clear account of the specific mechanism underlying this proposals. So, it seems plausible that the relationship between mindfulness and driving performance is indirect, and that personality traits such as conscientiousness and neuroticism may play a mediation role between mindfulness and driving performance. A sample of 98 drivers between the ages of 19 and 29 completed questionnaires assessing mindfulness, anxiety trait and anxiety state, and the big five personality traits. Driving performance was assessed in a driving simulator. A mediation model was fitted with conscientiousness and neuroticism set as mediators of the effects of the relationship between the subject’s mindfulness levels and the driving performance.     

Risky and anxious-aggressive drivers: A key barrier to traffic safety legislation in Germany

Traffic safety is high on the agenda of European governments. Yet, countries including Germany maintain policies that are commonly identified as increasing traffic risks, such as speed limits set too high or trends of greater car motorization and mass. To better understand some of the interrelationships of driver characteristics and car segments, this paper identifies different groups of drivers, based on a representative sample of German automobilists (n = 1211). Psychological instruments used to identify driver segments include the Driver Behavior Questionnaire (DBQ), the Multidimensional Driving Style Inventory (MDSI), and the HEXACO Personality Inventory. Based on k-means clustering, we identified four distinct groups: Risky drivers, Showy anxious-aggressive drivers, Anxious drivers and Calm drivers. Questions focused on socio-demographics, political orientation, and traffic laws are used to describe these psychographic segments. Findings suggest that Risky and Showy anxious-aggressive drivers represent a greater threat to traffic safety than other driver segments for different reasons: they drive more powerful and larger cars, deliberately violate traffic laws – creating unsafe traffic conditions for others –, and oppose legislation making traffic safer, while also voting for parties holding on to the status quo. As their political choices appear dominated by automobile interests, there are widespread implications for society.     

The effect of positive and negative emotions on young drivers: A simulator study

The study examined the influence of affect induction on actual risk-taking behavior in a driving simulator, as well as the links between personal variables (relevance of driving to self-esteem, sensation seeking) and the level of risky driving. Eighty young drivers aged 18–21 (M = 19.24, SD = 0.75) were randomly divided into four induction groups: relaxing positive affect; arousing positive affect; negative affect; and neutral affect. The participants drove on a simulator, with various parameters of risky driving measured before and after emotion priming.As predicted, arousing positive affect and negative affect led to increased risky driving, whereas relaxing positive affect moderated risk-taking. In addition, the results confirm previous findings regarding the personal variables, revealing that higher levels of relevance of driving to self-esteem and sensation seeking are associated with higher levels of risk-taking in the simulated driving.The findings indicate that the driver’s emotional state has a significant effect on risk-taking on the road. Moreover, they show that the conventional use of negative affect in safe driving campaigns is liable to heighten the tendency for risky driving rather than reduce it. In contrast, relaxing positive affect was found to lead to lower risk-taking. The study is unique in revealing a correlation between results previously obtained for the willingness to drive recklessly and actual risky driving behavior observed on a driving simulator. By expanding the understanding of the motivations for youngsters’ risky driving, the study may aid in designing effective, theoretically sound, interventions aimed at reducing the tendency for dangerous driving among young drivers.     

A qualitative study of young drivers and deterrence based road policing

Deterrence theory is the predominant theory used to underpin road policing initiatives. However, survey research indicates that this approach may not be as effective for young drivers. This study uses focus groups, conducted in both metropolitan and regional locations in two Australian states (Queensland and Victoria), to explore three components of classical deterrence theory: certainty, severity & swiftness. The results suggest that geographical context affected perceptions of certainty with individuals from regional locations less likely to indicate that they would be caught by police for committing a traffic offence. Additionally, the use of cameras to detect road offences increased perceptions of certainty for young drivers. The results of this study suggest that police agencies should focus on undertaking actions to increase the perceptions of certainty swiftness and severity of punishment, particularly in regional areas, for young drivers who engage in illegal behaviour on the road. Where appropriate, these actions should take into account the geographical context. There may also be value in considering augmenting deterrence theory with other theoretical perspectives for this group.     

An exploration of the effectiveness of in-person and online versions of the induced hypocrisy paradigm to reduce smartphone use among young drivers

Worldwide, smartphone use is a major contributing factor to road crash among young drivers. While young drivers may be aware of their heightened crash risk and the legal penalties associated with this behaviour, young drivers continue to engage with their smartphones. The development of novel interventions targeting this behaviour is therefore crucial. The current 2 × 2 between groups experimental study (N = 153, 107F, 43 M, 1 other) investigated the concept of cognitive dissonance in relation to smartphone use among young drivers aged 17–25 years (M_age = 20.66 SD = 2.26). Specifically, it applied the induced hypocrisy paradigm to this context. The induced hypocrisy paradigm elicits cognitive dissonance by asking participants to both advocate for the desired behaviour and identify their engagement in the undesired behaviour. Participants are then motivated to change their behaviour to reduce the feelings of dissonance. The current study investigated the efficacy of both the traditional in-person methodology with a new online methodology. Analyses (e.g., ANCOVA) found that the online conditions were more effective than the in-person groups at eliciting dissonance and that the intervention conditions were more effective in reducing both intention and change in behaviour (from pre- to post-intervention) than the control groups. The intervention groups were also more likely to take/request a flyer about driver distraction. While more research is needed to corroborate these findings, these initial results suggest that cognitive dissonance occurs when young drivers use their smartphones and that the induced hypocrisy paradigm may be an effective intervention. In particular, this study’s findings suggest that an online version of the induced hypocrisy paradigm has merit and may form part of future cost-effective, mass interventions.     

Driver responses to motorcycle and lead vehicle braking events: The effects of motorcycling experience and novice versus experienced drivers

In many countries, motorcyclists are over-represented in traffic collision fatalities and injuries compared to vehicle registrations. Why drivers may violate the right-of-way of motorcyclists traveling as lead vehicles in front of drivers is empirically examined in two studies that were conducted with a moderate-fidelity driving simulator. The purpose of the first study was to determine if drivers, who also held a motorcycle license (N = 16), drove cars differently than regular drivers (N = 16) around motorcycles. The two groups did not differ on responses to motorcycling braking events, which was consistent with previous research on car following. The second study compared the driving performance of sixteen novice teenage drivers (M = 16.2 years of age) to 15 experienced drivers (M = 32.9) over the span of six monthly simulator sessions. Novice drivers’ perception response times (PRT) to the braking events were significantly longer than those of the experienced drivers. PRTs to motorcycle and lead vehicle braking events decreased over sessions. For all participants, PRTs to the motorcycle events were longer than to the car events. The implications of these results for motorcyclists and drivers with different levels of experience are discussed.