Visuomotor control of steering: the artefact of the matter

Abstract

Previous behavioural research (Land and Horwood in Nature 377:339-340, 1995) indicates that surprisingly little visual information is required to effect smooth and accurate steering through a curving roadway. Based on results from a driving simulator study, Land and Horwood reported that viewing the roadway through two horizontal apertures, one degree of visual angle in height, can result in steering performance which is indistinguishable from that obtained with the whole scene visible. The position of the apertures in the visual field, they claimed, is crucial; higher up leads to less accurate but more stable steering responses, whilst lower down leads to jerky steering but more accurate lane-keeping. These findings are consistent with a two-stage model of steering control proposed by Donges in Human Factors 20:691-707 (1978). However, in a driving simulator, the temporal lag between the input signal received from a control device and the output presented on the display can have profound effects on steering behaviour. In two experiments, we show that the effect of aperture position on steering accuracy and stability is pronounced when a slow frame update rate is used (7.2 Hz, as used by Land and Horwood in Nature 377:339-340, 1995), but largely attenuated with a faster update rate (72 Hz). These results are consistent with the broader empirical literature dealing with temporal delays in manual tracking, and urge a critical reappraisal of the behavioural evidence for the two-stage steering model.

Optic flow speed modulates guidance level control: New insights into two-level steering.

“…However the current results do support Cloete & Wallis (2011), who failed to find clear indicators of a shift in control strategies in response to changes in road-edge information.…”

“…Therefore, it is likely that the instability effects in Experiment 1 were due to the slower refresh rate (Cloete & Wallis, 2011) and not due to removing near road-edges.…”

“…as per previous publications, specific vehicle dynamics were not simulated so as to reduce the amount of practice needed to achieve stable performance, e.g. Cloete & Wallis, 2011;Land & Horwood, 1995;Robertshaw & Wilkie, 2008;Wilkie & Wann, 2002, 2003b.…”

“…It can be seen that this measure does not explicitly relate to the requirement to maintain a position near the road midline so it is possible to steer very smoothly but completely erroneously. The literature that has examined near and far road components suggests that smoother steering should be observed when far road components are available, and less smooth when only near road-edge information is available (Cloete & Wallis, 2011;Frissen & Mars, 2014;Land & Horwood, 1995;Salvucci & Gray, 2004). FISB is a useful measure to simply examine the extent to which participants responded to flow speed under the different road-edge conditions.…”

“…Cloete & Wallis (2011) suggested that the low display L H H the observed steering effects. Comparing both lower and higher refresh rates (7.2Hz and 72Hz), Cloete & Wallis (2011) found that steering behaviour was less accurate (measured by standard deviation of the deviation from the road centre) and jerkier at the lower refresh rate, and that this effect was especially pronounced when only a near road segment was viewed. They did, however, replicate the finding that steering behaviour becomes increasingly jerky as guidance level information is removed (this interaction is reduced in 72Hz displays compared with the 7.2Hz refresh rate, but still consistent across participants; Cloete & Wallis, 2011).…”