Amanda N. Stephens

Anger-congruent behaviour transfers across driving situations

Anger and aggression on the road may sometimes appear unprovoked and unrelated to current driving circumstances. It is unclear whether such anger and aggression arises because of events prior to those circumstances in which anger is experienced and aggression is exhibited. In this study, time pressure and enforced following of a slowly moving vehicle were used to increase drivers’ anger in order to assess whether affect and behaviour during a subsequent, non-provocative, drive would change accordingly. Ninety-six drivers drove twice in a simulated urban environment. During the first drive, oncoming traffic and a slowly moving lead vehicle required that half of the drivers travelled far slower than they would choose. During the second drive, drivers again followed slower vehicles and were required to respond to traffic events not encountered in the manipulation drive. Mood (Profile of Mood States) was assessed before and after each drive, and anger evaluations, arousal (heart rate) and behaviour (speed, lane position and collisions) were measured during drives. Anger increased and both mood and driving behaviour deteriorated in drivers exposed to slower lead vehicles, compared with control group drivers. These behavioural differences of speed and lane positioning carried over into the subsequent drive even to driving situations unlike those where provocation had previously occurred. Drivers who had previously been impeded later approached hazards with less caution, and attempted more dangerous overtaking manoeuvres. It is concluded that sometimes dangerous driving may result from anger provoked by circumstances other than those in which the behaviour is exhibited.

The expression of anger amongst Turkish taxi drivers

The present study tested the four factor structure of the DAX on a sample of Turkish taxi drivers and the relationship these factors had with a number of other variables. Confirmatory Factor Analysis found that the data broadly fit the four factor solution of the DAX. These factors included three aggressive expressions: Verbal Aggressive Expression; Personal Physical Aggressive Expression; Use of a Vehicle to Express anger, and one Adaptive/Constructive factor. Driving experience was negatively related to the three types of aggressive expression. The Total Aggressive Expression was positively related to annual mileage and preferred driving speed, but negatively related to age and experience. The present research also found that the three aggressive types of anger expression were significantly related to potentially crash related conditions, such as losing control of the vehicle, loss of concentration and near-misses. However, none of the DAX factors was significantly related to either minor or major crashes.

A comparison of the Driving Anger Scale and the Propensity for Angry Driving Scale.

The present study investigated the factor structures of the 14-item version of the DAS (Driving Anger Scale) and the Propensity for Angry Driving Scale (PADS) using a sample of New Zealand drivers drawn from the general population. The two scales were also investigated with regards to their relationships with general trait anger, risky driving behaviour, along with crash involvement and a variety of crash-related conditions. Confirmatory Factor Analysis supported both scales as unidimensional, although the PADS was reduced from a 19-item to an 18-item scale. Both the PADS and DAS were significantly related to trait anger, risky driving behaviour and near-misses. However, once the influence of the demographic variables and trait anger had been partialled out, the addition of the PADS and DAS made a significant contribution to predicting violations, but it was only the PADS which was significant. In contrast, after the demographic variables and trait anger had been partialled out, the addition of the DAS and PADS again made a significant contribution to the prediction of near-misses, but this time it was only the DAS which made a significant contribution. The present study clearly shows that both scales are robust measures, measuring similar, but slightly different aspects of driving anger.

Driving anger in Malaysia

The present study examined the types of situations that cause Malaysian drivers to become angry. The 33-item version of the driver anger scale (Deffenbacher et al., 1994) was used to investigate driver anger amongst a sample of 339 drivers. Confirmatory factor analysis showed that the fit of the original six-factor model (discourtesy, traffic obstructions, hostile gestures, slow driving, illegal driving and police presence), after removing one item and allowing three error pairs to covary, was satisfactory. Female drivers reported more anger, than males, caused by traffic obstruction and hostile gestures. Age was also negatively related to five (discourtesy, traffic obstructions, hostile gestures, slow driving and police presence) of the six factors and also to the total DAS score. Furthermore, although they were not directly related to crash involvement, several of the six forms of driving anger were significantly related to the crash-related conditions of: near misses, loss of concentration, having lost control of a vehicle and being ticketed. Overall the pattern of findings made in the present research were broadly similar to those from Western countries, indicating that the DAS is a valid measure of driving anger even among non-European based cultures.

Effects of upper-limb immobilisation on driving safety

Doctors are frequently asked by patients whether it is safe to drive with an upper limb immobilised in a cast. In the literature there are no objective measurements of the effects of upper-limb immobilisation upon driving performance. Eight healthy volunteers performed four 20-min driving circuits in a driving simulator (STISIM 400W), circuits 1 and 4 without immobilisation and circuits 2 and 3 with immobilisation. Immobilisation involved a lightweight below-elbow cast with the thumb left free. Volunteers were randomised to right or left immobilisation for circuit 2, and the contralateral wrist was immobilised for circuit 3. Circuits included urban and rural environments and specific hazards (pedestrians crossing, vehicles emerging from a concealed entrance, traffic lights changing suddenly, avoidance of an oncoming vehicle in the drivers carriageway). Limb immobilisation led to more cautious rural and urban driving, with less adjustment of speed and lateral road position than when unrestricted. However when responding to hazards immobilisation caused less safe driving, with higher speeds, a greater proximity to the hazard before action was taken and less steering adjustment. The effects of restriction upon performance were more prevalent and severe with right-arm immobilisation. Upper-limb immobilisation appears to have little effect on the ability to drive a car unchallenged, but to adversely affect responses to routine hazards. Advice on ability to drive safely should be cautious, as the impact of immobilisation appears to be more subtle and wide ranging than previously thought.

Couples, contentious conversations, mobile telephone use and driving

Studies have shown that the inappropriate use of in-vehicle technology may lead to hazardous disruption of driver performance. This paper reports an investigation into the socio-technical implications of maintaining a difficult conversation while driving. Twenty romantically involved couples participated in a driving-simulator experiment. The participants engaged in emotionally difficult conversations while one partner drove. The contentious conversation topics were identified using a revealed differences protocol, requiring partners to discuss sources of ongoing disagreement in their relationship. The conversations were conducted either using handsfree telephone or with both parties present in the simulator. Results indicate that the revealed differences tasks were subjectively viewed as emotionally more difficult than a control. Driver performance was found to be adversely effected for both longitudinal and lateral vehicle control. Performance was worst during contentious conversations with the partner present, suggesting the drivers may be better able to regulate driving task demands with the partner not in the vehicle during difficult discussions.

Multiple driver distractions: A systemic transport problem

Strategies to contend with driver distraction may no longer be sufficient for the emerging variety of contemporary driver distractions. A more systematic and systemic approach holds promise for improved road safety but is not currently being developed. This systematic review of multiple driver distractions aims to address this gap and presents two key findings. Systematic classification of distracting tasks with respect to driving is challenging, and engagement with Multiple-Additional-to-Driving (MAD) tasks is almost universally detrimental to driving performance. A model is presented to assist in systematically characterising multiple driver demands. Identified literature is placed into context using the model and shortfalls are identified.

Development of a short form of the driving anger expression inventory

The present study developed a revised version of the driving anger expression inventory (25-items) and a short (15-item) version using data from 551 drivers. Split half factor analyses on both versions confirmed the original four factors; personal physical aggressive expression, use of a vehicle to express anger, verbal aggressive expression and adaptive/constructive expression. The two DAX versions were strongly correlated, demonstrating the suitability of both forms of the scale and the aggressive forms of expression were higher for drivers who reported initiating road rage interactions. Total aggressive expression was also higher for drivers who reported recent crash-related conditions, such as: loss of concentration, losing control of their vehicle, moving violations, near-misses and major crashes. The revised DAX and DAX-short provide shorter versions of the 49-item DAX that can more easily be combined with other questionnaires and require smaller sample sizes to analyse. Further research is required to validate these tools among different samples and populations.

Validation of the Driver Behaviour Questionnaire in a representative sample of drivers in Australia

The Driver Behaviour Questionnaire (DBQ) is a widely used measure of driving behaviours that may increase a drivers risk of crash involvement. However, there are several different versions of the DBQ varying in terms of number of items and factor structure. The aim of the current research was to assess the construct validity of the popular 28-item four-factor DBQ solution in a representative sample of drivers in Australia. A further aim was to test the factorial invariance of the measure across gender, age and also between fleet and non-fleet drivers using multigroup confirmatory factor analyses. Data on a range of attitudes towards road safety were collected using an online survey. A stratified sampling procedure was undertaken to ensure the age, gender and location distributions of participants were representative of the Australian population. A total of 2771 responses were obtained from fully licensed motor vehicle drivers (male: 46%). Confirmatory factor analysis supported the 28-item four-factor DBQ in the Australian sample. The DBQ was also found to be gender-invariant and strong partial measurement invariance was found for drivers aged from 26 to 64, but not for younger (17-25) or older (65-75) drivers. Modifications to the DBQ suggest how the DBQ can be improved for use in these two age groups.

The impact of working memory load on task execution and online plan adjustment during multitasking in a virtual environment

Three experiments investigated the impact of working memory load on online plan adjustment during a test of multitasking in young, nonexpert, adult participants. Multitasking was assessed using the Edinburgh Virtual Errands Test (EVET). Participants were asked to memorize either good or poor plans for performing multiple errands and were assessed both on task completion and on the extent to which they modified their plans during EVET performance. EVET was performed twice, with and without a secondary task loading a component of working memory. In Experiment 1, articulatory suppression was used to load the phonological loop. In Experiment 2, oral random generation was used to load executive functions. In Experiment 3, spatial working memory was loaded with an auditory spatial localization task. EVET performance for both good- and poor-planning groups was disrupted by random generation and sound localization, but not by articulatory suppression. Additionally, people given a poor plan were able to overcome this initial disadvantage by modifying their plans online. It was concluded that, in addition to executive functions, multiple errands performance draws heavily on spatial, but not verbal, working memory resources but can be successfully completed on the basis of modifying plans online, despite a secondary task load.