Shining Light on Retroreflectivity: Perceived Brightness of Surfaces with Varying Reflective Properties

Typical road users appear not to understand retroreflectivity despite nightly exposure to retroreflective materials such as road signs. While retroreflective surfaces have been engineered to reflect light back in the direction of its source, retroreflectors appear to be diffuse reflectors in most viewing conditions. This may lead road users to underestimate its value in nighttime roadway applications and contribute to vulnerable road users’ under-use of retroreflective markings to enhance their own conspicuity at night. In this context, a critical benefit of retroreflective materials is a robustness to changes in entrance angle, the angle at which the light strikes the material.This online study measured participants’ perceived brightness judgments for surfaces that represent three types of reflection (diffuse, specular, and retroreflective) with varying entrance angles. To assess the potential benefits of seeing retroreflectivity in action, perceived brightness was evaluated before and during a demonstration that includes illumination from a directional light source positioned near the recording camera. After seeing the visual demonstrations, participants’ brightness judgments revealed an enhanced appreciation that retroreflective (but not specular or diffuse) surfaces remain bright despite large changes in entrance angle. These findings could be utilized to design more effective and accessible video demonstrations of retroreflectivity in hopes of increasing the demand for retroreflective markings by vulnerable road users

Stakeholder Perceptions of Longer Trains

This report documents stakeholder perceptions emerging from focus groups about very long trains (VLTs) with participants from three labor unions, the Federal Railroad Administration (FRA), and two freight railroads. All stakeholders expressed uncertainty about how to define a VLT and noted that the safety of longer trains is related to additional contextual factors beyond train length. Views on specific safety concerns varied by stakeholder category. Railroad manager participants asserted that increasing train length does not pose new safety concerns. FRA participants shared some concerns, but their perspectives varied. Labor participants strongly asserted that VLT operations present new or increased safety concerns. The diverse set of factors identified as affecting safety do not fit easily into a framework for understanding the relationship between train length and safety. Further study is needed, and the Appendix include a list of questions to support future research

Interactive PowerPoint Training to Improve Safety Driver Awareness while Operating a Transit Vehicle Equipped with Driving Automation Features

As new technologies, such as advanced driver assistance systems (ADAS) and automated driving systems (ADS) are introduced into transit operations, the tasks required of the operator will change. This research effort sought to understand if a low-cost training tool could be developed to maintain/improve safety as transit agencies pilot test these technologies. The program that was developed used an error training approach to improve hazard anticipation, hazard mitigation, and attention maintenance. This preliminary pilot study was conducted with federal employees and showed significant improvements across all three of the training areas