Speed maintenance under cognitive load – Implications for theories of driver behaviour

Abstract

No model of driver behaviour has yet managed to achieve widespread acceptance and use in the field of traffic psychology, par tly due to the difficulty in testing many of the theories. However, one class of theories, the motivational theories, can be usefully split into two groups, and the differences between them can then be examined. One group posits the constant monitoring and targeting of a cer tain subjective variable, often risk, as the controlling factor in driving. The other group however states that subjective variables such as risk are only relevant once a cer tain threshold has been passed.In this study we aimed to examine this difference by manipulating both speed of travel and the amount of cognitive load par ticipants were under. Par ticipants were asked to initially drive at their preferred speed for 1 minute in a driving simulator. Par ticipants' speed was then automatically increased or decreased by 10, 20, 30 km/h or left unchanged. Par ticipants were then required to maintain the new speed for 1 minute. After this 1 minute, the speed was again automatically changed and had to be maintained for one more minute, but this time par ticipants also carried out a secondary mental arithmetic task. Finally, par ticipants were asked to again drive for another 1 minute at their preferred speed. This procedure was repeated seven times, once for each speed manipulation; -30, -20, -10, +0, +10, +20 and +30 km/h. After each 1 minute interval, verbal ratings of task difficulty, effor t, feeling of risk, and the typicality of the speed, were collectedThe results show a threshold effect in ratings of task difficulty, effor t and feeling of risk, with no significant difference given between the ratings during the baseline period and the experimentally decreased speed periods until after par ticipant's preferred speed of travel had been exceeded. Fur thermore, even when under cognitive load the threshold relationship was still apparent, if somewhat diminished. Finally, it appears that when under cognitive load drivers have difficulty maintaining a travelling speed which is lower than the speed at which they would prefer to drive. However, driving at a speed in excess of their preferred speed appears to be easier to maintain, at least in the shor t term. 3Speed maintenance under cognitive load -Implications for theories of driver behaviour

Cognitive workload and driving behavior in persons with hearing loss

“…This more cautious driving behavior could be a way of compensating for or adapting to the greater effect on the HL group when driving complexity increased. The driver behavior adaptation (or compensation) observed, decreased driving speed, and disregard of the Secondary task conforms well with previous research (Fuller, 2005;Lewis-Evans, 2011). The finding that the phonological similarity effect only affects the HL group more in critical situations also points at the effect of driving complexity.…”

“…Manipulation of driving speed along with degree of engagement in Secondary tasks is claimed to be the primary mechanisms for this maintenance (Fuller, 2005). Simulator studies have demonstrated that distraction tasks (both visual and cognitive) lead to decreased speed and a difficulty in maintaining a certain speed (Engström, 2005;Lewis-Evans, 2011). Tsimhoni (2003) found, in a driving simulator study with a Secondary task and varying complexity of the road condition, that the total time allocated to the Secondary task increased significantly with a more complex driving task (sharp curves vs. straight road vs. parking).…”

“…Among the factors determining the driving task demand, of which the driver has immediate and direct control, driving speed is the most significant (Fuller, 2005). It has been demonstrated that when a threshold of a certain preferred driving speed is exceeded, experienced task difficulty, effort and feeling of risk is affected (Lewis-Evans, 2011). Normal driving can be considered as a cognitive and controlled task, and thus one approach to understand driving behavior is using cognitive psychology.…”

Simulating the effect of cognitive load on braking responses in lead vehicle braking scenarios

“…The same general pattern of results, where CL selectively impairs non-automatized aspects of driving, has also been demonstrated for other aspects of driving performance such as lane keeping [28], speed selection [29,30] and gap acceptance at intersections [31] (again see [2] for a detailed review).…”

Classifying visuomotor workload in a driving simulator using subject specific spatial brain patterns

“…At this point there is no consensus about the exact psychological processes underlying driving behavior. Depending on the theoretical framework, the level of (subjective) risk, workload, or a general feeling of comfort is either maintained or avoided (e.g., risk homeostasis theory, the zero-risk theory, risk allostasis theory, safety margin model (Näätänen and Summala, 1976; Wilde, 1982; Fuller, 2005; Summala, 2005; see also: Lewis-Evans et al, 2011). To make it even more complex, drivers alter the level of workload in practice through behavioral adaptations.…”