Fellows Aysheh and Nima have submitted their theses

Our fellows Aysheh Alshdaifat (ESR 10) and Nima Hafezparast Moadab (ESR 11) both researchers at the University of Sheffield have submitted their PhD thesis!

Congratulations with this achievement and good luck with your defence!

Nima focused on “Countering distractions to visual detection when driving after dark.”

On main roads, such as motorways and dual carriageways, road lighting is designed to meet the needs of drivers. Well-designed road lighting is intended to support visual performance and visual comfort after dark, and therefore this has been the dominant concentration of previous research. Less attention has been paid to the extent to which lighting can support driver attentiveness, a critical factor for driving since failure to give sufficient attention is a causal factor in many road traffic collisions. Therefore, this thesis reports further investigation of the extent to which light can be utilized to mitigate drivers’ inattention due to sleepiness or distraction.

Aysheh focused in her research on “Investigating the cognitive alerting effect of lighting for walking in the evening”

One key purpose of road lighting is to allow road users to proceed safely. On minor roads, road lighting is designed to meet the needs of pedestrians and cyclists. One issue not directly addressed by current guidelines for designing outdoor lighting is whether they are in line with ongoing understanding of non-image-forming effect (NIF) and unwanted side-effects of road lighting. Enhancing alertness could make the pedestrian more alert to potential hazards and could enhance visibility and the visual perception to detect dangerous objects. A lack of alertness may contribute to road traffic collisions and pedestrian falls injuries.

In this study, two laboratory tests have been conducted to investigate the NIF effect of road lighting in a context representing pedestrians. The aim of the experiments was to explore the effect of lighting on pedestrian alertness at evening, using lighting conditions typical of outdoor lighting. Three tests were conducted: saliva melatonin level, auditory – Psychomotor vigilance task (PVT), and Karolinska Sleepiness Scale (KSS).

Results of the two experiments suggested that for melanopic EDI of up to 10.7 lx, there was no significant effect on alertness. However, increasing the melanopic EDI to almost 100 lx revealed significant reductions in reaction time (RT), subjective sleepiness, and a decrease in melatonin. Changing positions from sitting to standing increased melatonin concentration after 30 minutes, while walking at a moderate speed significantly shortened the RT after 30 minutes and enhanced subjective alertness. The results of this study do not suggest that road lighting has a significant impact on the alertness of pedestrians, and thus would not affect the choice of optimal lighting conditions.

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