Improving Pedestrian Conspicuity at Night: Testing the Efficacy of an Educational Intervention

Abstract

Most pedestrian fatalities happen at night, and poor conspicuity has been identified as a critical problem. Researchers understand what typical pedestrians do not: At night, a pedestrian’s conspicuity heavily depends on contrast and the presence or absence of retroreflective markings and biological motion. This experiment aims to evaluate the impact of an 11-min educational video that explains these critical concepts. Half of the participants will view the video while the other half will not. All participants will provide quantitative estimates of the nighttime conspicuity and safety of a pedestrian wearing each of five clothing configurations. We hypothesize that participants who view the video will exhibit improved comprehension of safety-relevant concepts and the visual challenges experienced by drivers at night. This research could underscore the value of online interventions in educating road users about critical concepts that impact nighttime conspicuity, thereby encouraging them to adopt evidence-based methods to enhance their conspicuity.

Objectives

The majority of pedestrian fatalities occur at night, and insufficient conspicuity has repeatedly been implicated as a causal factor. Thus, there is a critical need for innovative strategies to educate road users about nighttime visibility issues. Studies have repeatedly documented that pedestrians at night frequently have insufficient contrast to be detected by drivers from a safe distance (see Tyrrell et al., 2016). Even when headlighting is present, contrast is limited by the fact that diffuse reflective surfaces (including typical clothing materials) scatter headlight illumination in many directions at once with only a small portion being directed back toward the driver.

Retroreflective materials, on the other hand, are engineered to increase contrast at night by directing reflected light back toward the light source. Road users regularly encounter retroreflective materials. They are used in road signs, on large trailers, in lane delineation, in road work zones, and on vehicles and uniforms used by first responders. Researchers have confirmed that positioning retroreflective materials on pedestrians enhances their nighttime visibility (Tyrrell et al., 2016). Further, when the retroreflective materials are positioned on the pedestrian’s extremities in a “biological motion” configuration the pedestrian’s conspicuity is further enhanced. Despite compelling scientific evidence supporting the effectiveness of retroreflective materials in this domain, it remains unusual for typical pedestrians to make use of retroreflective materials (e.g., Wood et al., 2009).

One possible reason why pedestrians do not feel compelled to make use of retroreflective materials at night is that they that they may fail to appreciate how inconspicuous they are to drivers at night. Consistent with this possibility is the finding that at night pedestrians typically overestimate their visibility to approaching drivers (e.g., Shinar, 1984). Worse, pedestrians tend to overestimate their own nighttime visibility the most when they wear low reflectance clothing (Tyrrell et al., 2004).

A complicating factor is that pedestrians appear not to understand retroreflectivity. Recently, King et al. (2023) provided compelling evidence that typical road users do not appreciate that retroreflective materials will appear remarkably bright when they are illuminated by a light source that is aligned with their eyes. This is understandable given that (a) retroreflective materials do not appear particularly bright when they are inspected in typical room illumination conditions, and (b) the concept of retroreflectivity is not included in driver education curricula. Taken together, these results suggest that road users could benefit from being educated about issues surrounding nighttime visibility and conspicuity. Educational interventions have been shown to be effective in this domain (Whetsel Borzendowski et al., 2014; Tyrrell et al., 2004). However, those studies relied on a subject matter expert providing in-person lectures that reach only a small group of road users at a time.

The purpose of this experiment is to quantify the impact of a brief video of a subject matter expert discussing nighttime visibility issues.

Approach

The intervention video, which is 11 min long, focuses on the selective degradation of focal visual functions, contrast, retroreflectivity, and biological motion. The video utilizes compelling visuals and clear explanations including several brief video clips of pedestrians wearing various garments walking in both daytime and nighttime conditions. The video content addresses road users’ common misconceptions and knowledge gaps regarding nighttime visibility. The intervention is intended to encourage pedestrians to apply these concepts to enhance their own conspicuity thus mitigating the risks of interacting with traffic at night.

The study will employ a mixed-methods approach, combining quantitative and qualitative measurements. Participants will be randomly assigned to one of two groups: the control group will not see the intervention video. The intervention group who will have watched the video shortly before data collection began. A variety of measures will be evaluate the impact of the intervention. The participants will see daytime photographs of a pedestrian wearing five different clothing configurations that have been demonstrated by previous research to vary in nighttime conspicuity. The configurations varied from an all-black outfit to a full “biomotion” configuration of retroreflective markings. For each configuration, the participants will imagine that the pedestrian is walking in the roadway at night and they will estimate (a) the distances at which drivers would recognize that a pedestrian is present on the roadway, (b) the perceived visibility, and (c) the safety of the pedestrian. Participants will also rank the visibility of the clothing configurations. Further, the participants will respond to a list of comprehension questions that will assess how well participants understood the concepts in the video. Participants in the intervention group will also participate in a debriefing session to give qualitative feedback on the video to better inform future iterations.

Findings

It is expected that the findings will align with previous research findings from in-person interventions. It is predicted that participants exposed to the intervention video will demonstrate enhanced knowledge and understanding of nighttime visibility concepts relative to the control group. Overall, the intervention group is expected to estimate shorter recognition distances than the control group for pedestrians wearing no retroreflective markings. However, the intervention group is expected to estimate greater recognition distances for the pedestrians wearing retroreflective markings. The intervention group is expected to maximize their appreciation of the conspicuity of the pedestrian who is wearing retroreflective markings in a biological motion configuration.

Takeaways

This research highlights the proposed impact of educational interventions on enhancing pedestrian safety. By increasing awareness of key visibility concepts, pedestrians can make informed choices to enhance their visibility to approaching drivers and thereby reduce the risks associated with interacting with traffic at night.

A critical element of the current intervention is its ability to be administered online. This medium is advantageous because it can be delivered to many individuals asynchronously. It is also hoped that the data from this experiment will facilitate the development of a new and improved intervention video so that it will be even more effective for increasing the safety of pedestrians at night. Future studies are expected to re-examine the efficiency of these redesigned videos, test the effects in different viewing settings, and determine the long-term benefits of the intervention. Taken together, it is hoped that these efforts will yield effective educational interventions that encourage vulnerable road users to take advantage of evidence-based strategies to enhance their conspicuity, and thereby reducing the frequency and severity of relevant nighttime crashes.