4.3 Conspicuity Enhancement

Enhancing conspicuity for pedestrians increases opportunity for drivers to see and avoid pedestrians, particularly when it is dark, since this is when 75% of pedestrian fatalities occur nationally (NHTSA, 2020). Pedestrians who are more visible are less likely to be struck. A comprehensive review performed by Tyrrell et al. (2016) describes research methods and findings from over 124 publications that have quantified the effect of visual factors on perceiving pedestrians at night. This review describes the  aspects of night vision that limit the conspicuity of pedestrians based on twilight and nighttime settings, poor retroreflective markings, headlight beam ranges, and visual impairment. This literature summarizes visual challenges at night and provides evidence of human efficacy to detect pedestrians due to a natural visual sensitivity to perceive biological motion. Based on the research reviewed, conspicuity is greatly enhanced at night regardless of any visual clutter when pedestrians are in motion and use retroreflective clothing, especially on their extremities. This summary emphasizes the importance of enhancing educational interventions to raise awareness for pedestrians of visual risks at night due to the  visual conditions, and it suggests directing future research towards promoting the use of wearing retroreflective garments.

Retroreflective materials that reflect light are built into many shoes, including children’s and athletic shoes. Other accessories such as arm or leg bands, gloves, vests, and caps are available from sporting goods stores and other vendors. Light sources including strobes and other flashing lights, are also available. Many have been designed for bicyclists but are equally applicable to pedestrians. The difficulty with most of these devices is that the user must decide in advance to take and use them. Due to the extra step and the appearance of the conspicuity enhancements not looking like “normal” clothing, they are very much underused. Pedestrians also tend to overestimate their own visibility, wrongly assuming if they can see vehicles, vehicles must see them (Karsch et al., 2012). See also the Bicycle Safety chapter, Section 3.1 on bicyclist conspicuity measures for more information. Bright colors and fluorescent clothing may also help to improve daytime conspicuity for pedestrians in some environments, but most research has focused on bicyclists and there may be differences in effectiveness for these groups. Adding electroluminescent (EL) garments to other retroreflective clothing improves pedestrian conspicuity at night. A nighttime on-road evaluation found that the addition of EL garments resulted in vehicles reacting sooner to pedestrians farther outside the vehicle’s headlight light beam (Fekety et al., 2016). Increasing pedestrian's visibility with retroreflective and EL garments provided the greatest benefits to pedestrians in situations when vehicles are approaching pedestrians from a curve or when vehicles’ head lights are turned off.

Nearly 14% of pedestrian fatalities in 2018 involved pedestrians who were not visible – dark clothing, no lighting, etc. (NHTSA, 2020). There are opportunities for improving pedestrian conspicuity. NHTSA’s child education program includes information about conspicuity messages targeting different age groups. (See www.nhtsa.gov/pedestrian-safety/child-pedestrian-safety-curriculum.) Other educational efforts should include a focus on being visible at night and in the daytime and making use of the conspicuity aids described in this section. Devices designed to be semi-permanently fastened to children’s clothing can be provided to parents through schools, group activities, or health care providers. Light sticks and reflective bands can be supplied with new cars, or distributed by automobile clubs or insurance companies for use during vehicle breakdowns or emergencies. In these cases, drivers become pedestrians in potentially vulnerable locations on the roadside (e.g., changing a flat tire), where other drivers may not expect them. Thus, pairing visibility devices with the vehicle provides a way for these unintentional pedestrians to remain visible regardless of their level of preparation.

Use: Retroreflective materials are used regularly in athletic-type shoes, occasionally in backpacks and jackets, and minimally in other clothing.

Effectiveness: Widespread use of retroreflective materials would increase the ability of drivers to detect pedestrians at night in time to avoid crashes. Pedestrians wearing good retroreflective materials, particularly materials that highlight a person’s shape and moving extremities (i.e., wrists and ankles), or widespread use of active (flashing) lights can be detected hundreds of feet farther than can pedestrians in normal clothing, even with low-beam illumination (Koo & Huang, 2015; Karsch et al., 2012; Zegeer et al., 2004, Strategy B5). A study in a controlled (closed road) environment also validated that pedestrians are detected more readily when they wear reflective elements on their moving body parts rather than attached to the torso (Tyrrell et al., 2009).

Costs: The cost to provide retroreflective materials is low, if such supplementary materials are distributed in quantity and added to existing programs. Such items as reflective wrist and ankle bands are available commercially. To develop new programs promoting use of conspicuity materials would require somewhat more planning and start-up time and costs would also depend on communications strategies used.

Time to implement: Promoting increased conspicuity may require development of targeted messages and a publicity strategy.