How Well Do Drivers Understand Their Own Headlights?

The current research represents an initial investigation of drivers’ understanding of high beam and low beam headlight patterns in a nighttime driving environment. Fifty-four university students used a highlighter to indicate on a paper diagram of a roadway scene the portion of the scene that they felt their headlights would illuminate. Although the headlight patterns produced by participants varied more than expected, several consistent patterns emerged. Classification and evaluation of these drivers’ responses revealed that many drivers misunderstand the area of the roadway that is illuminated by their headlights. These misunderstandings fall into fairly distinct patterns. The results indicate many drivers possess an incomplete understanding of the pattern of illumination provided by their headlights. These results are consistent with earlier evidence that many road users fail to appreciate the visibility challenges that exist at night

The conspicuity of first-responder safety garments

A study was conducted on a closed track in both daytime and nighttime conditions to compare the conspicuity of three different types of safety garment for use by first responders; NFPA 1971 turnout gear coats, and ANSI/ISEA 107 and 207 safety vests. Eight participants, balanced for gender and age, drove instrumented vehicles on the closed track indicating the distance at which they could detect pedestrians in a simulated emergency response scene. Pedestrians, wearing one of the safety garments, stood adjacent to the emergency scene, on either the right or the left side, oriented either facing or perpendicular to oncoming traffic. The effect of pedestrian motion on detection was also examined by having pedestrians stationary or walking in place. The results show that there was no statistically significant difference in the distance at which pedestrians were detected, regardless of which garment was worn. In other words, all three standards of garment provided equal levels of conspicuity under the conditions examined. Time of day was a significant factor, with mean detection distances being longer during the daytime for all garments. Pedestrian orientation was significant, with mean detection distances being longest when facing traffic, but pedestrian motion did not result in significant differences in detection distance. The results suggest that all of the garments studied should be considered equivalent relative to making first responders conspicuous when working in close proximity to traffic.University of Michigan Industry Affiliation Program for Human Factors in Transportation Safetyhttp://deepblue.lib.umich.edu/bitstream/2027.42/58734/1/100881.pd

A Comparative Analysis of Electroluminescent and Retrorefelective Materials as Nighttime Pedestrian Conspicuity Aids

Recent literature suggests that retroreflective materials, when configured in a biological motion pattern, make vulnerable road users (such as pedestrians) more conspicuous to drivers at night. However, retroreflective elements in clothing can be effective only when a light source (e.g., automobile headlamps) illuminates the material in such a way as to allow the material to reflect sufficient light back to the eyes of the driver. Thus, retroreflective materials are not useful for pedestrians who are positioned outside the beam pattern of an approaching vehicle\u27s headlamps. Electroluminescent materials, flexible light sources that can be attached to clothing, have the potential to enhance conspicuity in these conditions. This project investigated the conspicuity benefits of adding electroluminescent material to clothing that contains retroreflective elements. Using an open-road course at night, the current work compared the distances at which observers responded to pedestrians wearing one of two different kinds of high-visibility garments, who were at one of three different lateral positions relative to the vehicle\u27s path. The results show that a garment containing both electroluminescent and retroreflective materials yields longer response distances than garments containing only retroreflective material, particularly when the test pedestrian is positioned farther outside of the area illuminated by an automobile\u27s headlamps. These findings suggest electroluminescent materials can be especially useful to enhance the conspicuity of pedestrians who are outside a vehicle\u27s headlamp beam

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

The Effects of Headlight Intensity and Clothing Contrast on Pedestrians\u27 Own Estimated Recognition Distances at Night

Inadequate pedestrian detection is a crucial contributing factor in fatal nighttime collisions involving pedestrians. Pedestrians typically overestimate how recognizable they are to oncoming drivers and little is known about what affects pedestrians\u27 estimates of how recognizable they think they are. This study explored the extent to which pedestrians believed their conspicuity was affected by headlight intensity and clothing reflectance. Participants in four clothing conditions and in four different levels of headlight intensity walked to and from a parked vehicle until they felt recognizable to the driver. Estimated recognition distances did not change with variations in headlight intensity, suggesting that pedestrians do not use headlight illumination when judging their own conspicuity. Participants estimated shorter recognition distances when in Black clothing compared to more reflective clothing. These findings indicate a need to educate pedestrians about night visibility issues

Observers\u27 Judgments of the Effects of Glare on Visual Acuity

Traffic collisions and pedestrian fatalities increase significantly when driving at night. There is a need for greater roadway visibility when driving at night and the use of high beam headlights can significantly improve the distance at which drivers recognize objects along the roadway. However, research suggests that drivers underuse their high beams. It is possible that drivers do not use their high beam headlights in an effort to minimize glare to oncoming vehicles. The purposes of this experiment were to extend earlier research indicating that the visually impairing effects of glare may often be exaggerated and to investigate the role of stimulus contrast and size in observers\u27 judgments of the effects of glare. Participants were asked to judge the luminance of a glare source sufficient to impair their visual acuity of a target viewed through this glare source; these estimated glare thresholds were compared to the participant\u27s actual glare thresholds. Participants overestimated the intensity of glare required to produce a decline in their visual performance. On average, estimates of glare threshold were 88% lower than actual glare threshold values. Participants took stimulus size into account when making their estimates of glare threshold but did not seem to consider stimulus contrast information when making these judgments. The results of the current study confirm the trend seen in earlier work indicating that drivers exaggerate the debilitating effects of glare and are not fully aware of the actual effect of glare on their visual performance

THE ACCURACY OF DRIVERS\u27 PERCEPTIONS OF THE EFFECTS OF HEADLIGHT GLARE ON THEIR ABILITY TO RECOGNIZE PEDESTRIANS AT NIGHT

Recently, researchers have begun to assess the extent to which drivers believe their ability to see is degraded by headlight glare. Research has suggested that drivers may overestimate the extent to which glare from headlamps degrades their ability to see letters. This project extended this research by quantifying the accuracy with which drivers judge that glare interferes with their ability to see pedestrians at night. On average, participants overestimated the distance at which drivers would see a pedestrian by a factor of more than three. Headlight glare disrupted participants\u27 ability to recognize the pedestrian wearing both non-retroreflective and reflective clothing configurations. Interestingly, participants judged that headlight glare would not affect recognition distances for a pedestrian wearing a retroreflective vest, while judgments of recognition distances for the lower contrast pedestrian decreased appropriately. Future research should explore situations in which drivers\u27 misjudgments of their own perceptual capabilities may cause predictable problems

ENCOURAGING THE APPROPRIATE USE OF HIGH BEAM HEADLAMPS: AN APPLICATION OF THE THEORY OF PLANNED BEHAVIOR

Drivers typically underuse their high beam headlamps at night even under ideal conditions (i.e., no leading, following, or oncoming vehicles). One explanation for this is a lack of knowledge regarding both the magnitude of visibility problems at night and the benefits that high beams provide. The purpose of the present study was to design and evaluate an educational intervention based on the Theory of Planned Behavior (TPB) that targeted a more appropriate reliance on high beams. The results of Study 1 indicated that attitudes toward high beams best predicted intentions to use high beams. This information informed the design of an intervention delivered and evaluated in Study 2. TPB components accounted for 41% of the variance in intentions to use high beams and 38% of the variance in high beam usage. The educational intervention and implementation intentions did not significantly increase drivers\u27 use of high beams. Future research should continue to investigate predictors of high beam use and additional ways in which drivers can be encouraged to use their high beams appropriately

ARE DISTRACTED DRIVERS AWARE THAT THEY ARE DISTRACTED?: EXPLORING AWARENESS, SELF-REGULATION, AND PERFORMANCE IN DRIVERS PERFORMING SECONDARY TASKS

Research suggests that driving while talking on a mobile telephone causes drivers not to respond to important events but has a smaller effect on their lane-keeping ability. This pattern is similar to research on night driving and suggests that problems associated with distraction may parallel those of night driving. Here, participants evaluated their driving performance before and after driving a simulated curvy road under different distraction conditions. In experiment 1 drivers failed to appreciate their distraction-induced performance decrements and did not recognize the dissociation between lane-keeping and identification. In Experiment 2 drivers did not adjust their speed to offset being distracted. Continuous feedback that steering skills are robust to distraction may prevent drivers from being aware that they are distracted