Task Analysis: Using a Roundabout in the U.K.
by Dipl.-Psych. Sebastian A. Wagner, B.Sc. (F.C. Hon.) in Psych. University of Bamberg, Germany
This report examines the task of using a roundabout in the United Kingdom (UK). It considers a special population: motorists who are not use to driving on the left. There seems to be no purely psychological literature existent about the issues with left-hand versus right-hand driving or roundabouts. Therefore, the report is a first attempt to gain insight into the subject matter and works from first principles. Firstly, it will describe the task ‘using the roundabout’. Secondly, the user population will be specified. Thirdly, using the Hierarchical Task Analysis (HTA; Sheperd, 2000; cited in Mills, 2007) the crucial aspects of the task will be described. Fourthly, positioning the task in a psychological context the main psychological factors and their inter-relations will be evaluated. Finally, solutions for the issues found and methods for further investigations will be introduced.
The task of ‘using a roundabout’
A roundabout is a type of road junction, whereupon the traffic enters a one-way stream around a central island. For this report, it is assumed that it has four turnoffs, and consequently three lanes. Hels & Orozova-Bekkevold (2007) stated that roundabouts represent a more challenging orientation task because of their circular design, which may raise the risk of accidents. This suggests that the task of using a roundabout has psychological issues with regard to an ergonomic perspective.
The report focuses on people from overseas driving a car, i.e. the general public. It is generally known that in other European countries, law regulates right-hand driving (Lucas, 2008). This suggests that tourists have problems with driving on the left-hand side, because they are not use to it. The report considers this population of drivers. This is an important issue to explore, because it can be presumed that UK citizens also have problems driving on the right side, when they are overseas.
Mills (2007, p. 501) noted the HTA belongs to “task description methods, focusing on crucial aspects of the task within the context of the overall task”. It breaks down the overall goal into subordinate operations and plans. Here, the overall task ‘using a roundabout’ was broken down into four subordinate operations, which are used for a cognitive walkthrough (Jordan, 1998; Connell, Blandford & Green, 2004). Its aim is to approach the subsequent evaluation of the pertinent psychological factors and their inter-relations from the point of view of drivers trying to perform the task.
A basic HTA of ‘using a roundabout’ revealed the following observable operations:
(1) Chose lane
(3) Enter roundabout
(4) Turn off
II. Evaluation of psychological factors and inter-relations
Positioning the task in a psychological context
Raymond B. Cattell (1944; cited in Schlag, 1999) regarded human behaviour in the road traffic - this includes driving - as a miniature situation, i.e. it is representative for human behaviour in general. There is basically no aspect that does not play a role in this connexion, for example cognition, perception, learning, motivation, and individual differences. Schlag’s (1999) main themes regarding to accidents - conformity to traffic, risk balancing, and the accident personality - will be applied to left-hand driving.
Conformity to traffic means bearing in mind the system and safety aspects (Schlag, 1999). That is, drivers who are not use to left-hand driving must always consider the different system prevailing in the UK. For example, if there are no cars on the street (no cues for left-hand traffic), they still must be aware of the left-hand traffic to avoid accidents. Risk balancing means to counteract consciously in risky situations (Schlag, 1999). That is, tourists driving in the UK must be one hundred percent attentive. This includes avoiding secondary task interference, e.g. cell phone conversations (Horrey & Wickens, 2006; Young & Stanton, 2007) or listening to the radio (Brown, 1965). Marbe (1926; cited in Schlag, 1999) suggested that there is such a thing like accident proneness. In this connexion, Schlag (1999) reported that 25 - 30 % of the variance in the event of an accident is due to the drivers’ personality, i.e. there is a general issue with individual differences and driving. It also means, driving on the left does not change the fact that individual differences play an important part, e.g. in terms of anxiety or attention (Matthews, Davies, Westerman & Stammers, 2000).
In the worst case, an accident occurs while driving on the left. Accidents can be the result of errors in the broader sense. Reason et al. (1990; cited in Matthews et al. , 2000) conceived driving errors as distinct from violations. Errors are unintended actions, which are skill-based, rule-based, or knowledge-based and they are also attributable to deficiencies in information processing (Matthews et al. , 2000). In the following, these underpinning causes of errors as well as information processing theory are discussed in relation to the task ‘using a roundabout’. It can be assumed that untrained driving on the left requires a lot of effort regarding the cognitive resources of an individual (cp. Sweller, 1988). This will be discussed in terms of mental workload (Matthews et al. , 2000).
(1) Chose lane
Approaching the roundabout, drivers must choose a lane. This is a critical decision with psychological issues: it affects at which turnoff drivers can leave the roundabout later on.
Driving on the left is difficult enough, e.g. driving in a new environment (Schlag, 1999). Additionally, drivers approaching the roundabout are under time-pressure and consequently must make a quick decision about the lane. Recarte & Nunes (2003) suggested that the difficulty to perform a task is heightened when it requires a process of evaluation. Therefore, driving on the left and making a decision at the same time results in a heightened task difficulty. However, how does task difficulty relate to human performance?
Dual task performance - which requires divided attention - can be defined as “simultaneously to perform more than one task” (Matthews et al. , 2000, p. 88). It is constrained negatively by task difficulty. For example, Wickens (1980; cited in Matthews et al., 2000) showed that as memory load is increased tracking detoriates. This suggests that driving on the left and decision making at the same time might lead to a decreased performance of the task ‘using a roundabout’ – which might result in an accident.