The range of visual detection of ground-level cues during distracted walking: Effect of cue contrast and walking speed.

Walking while distracted by a smartphone has been a major safety concern for pedestrians. Visual and cognitive attention paid to the smartphone while walking with the head tilted downward would affect the ability to perceive walkway hazards and elevate risks for pedestrian accidents associated with physical contact with obstacles. A laboratory experiment was conducted to evaluate the performance of detecting ground-level visual cues during texting while walking. Forty young smartphone users performed walking trials at faster, preferred, and slower speeds for the dual-task walking on a treadmill and detected approaching cues of three contrast levels. Detection distance was quantified from the location of cue detection to the participants to assess the effects of walking speed and cue contrast on detection performance. Results show that detection distance varied from 1.7 m to 2.9 m for Low to High contrast cues and from 2.3 m to 2.5 m for Slower to Faster walking speeds, and the effects of contrast and speed were statistically significant (p < 0.05). Study findings suggest that higher contrast fixtures or in-ground signals and slower walking would help smartphone users perceive walkway hazards and in-ground safety signals earlier during their distracted walking.

Factors Influencing Pedestrian Smartphone Use and Effect of Combined Visual and Auditory Intervention on "Smombies": A Chinese Observational Study.

Objective: This was a large-scale multicenter study with two objectives. One was to study the factors influencing pedestrian smartphone use while crossing roads, and the other was to study the effect of combined visual and auditory intervention on smartphone zombies (smombies) at crossroads. Methods: This study was conducted in four different Chinese cities. By observing pedestrians crossing intersections, the weather, time, and characteristics of the pedestrians were recorded by four researchers. Then, its influencing factors and the effects of the intervention were studied in two consecutive periods. Results: A total of 25,860 pedestrians (13,086 without intervention and 12,774 with visual and auditory intervention) were observed in this study. Logistic regressions showed that gender, age of the pedestrians, weather, and time were the factors influencing smombies crossing roads. The number of smartphone users decreased from 4,289 to 3,579 (28.1%) (χ 2 = 69.120, p < 0.001) when the intervention was conducted. Conclusion: Based on large-sample, multicenter research, this study revealed the factors influencing pedestrian smartphone use while crossing roads, contributing to our understanding of the current situation of smombies in China. Furthermore, the effect of visual and auditory intervention was demonstrated, providing a new paradigm for global prevention of smombie behavior.

Neck Muscular Load When Using a Smartphone While Sitting, Standing, and Walking.

OBJECTIVE: Myoelectric activity of neck extensor muscles and head kinematic variables, when using a smartphone for one-handed browsing and two-handed texting while sitting, standing, and walking, were evaluated to compare the neck muscular load during these tasks and across the posture conditions. BACKGROUND: There has been limited research on the relation between head-down postures and the muscular load on the neck of smartphone users. METHODS: Twenty-one asymptomatic young users were asked to perform one-handed browsing and two-handed texting tasks in each of the posture conditions, and the myoelectric activities of the neck extensor muscles, head kinematic variables, and upper back posture were quantified. RESULTS: The muscle activation level when using a phone during walking was 21.2% and 41.7% higher than that of sitting and standing on average (p < .01). Head vertical and angular accelerations were also significantly greater (p < .01) for walking than for sitting and standing conditions. Between the two conducted tasks, participants flexed their heads more significantly (p < .01) with higher activation of the neck extensor muscles (p < .01) when texting as compared to when browsing. CONCLUSION: Results indicate that two-handed texting while walking would be the most physically demanding scenario for neck musculature, and it might be attributable to the dynamics of the head while walking with the head facing downwards. APPLICATION: These findings can be used to better understand the potential relation between smartphone use and the occurrence of neck musculoskeletal problems and to inform the users of the ergonomic risks of using smartphones while walking.