Jeremiah Singer

Volvo and Infiniti Drivers’ Experiences With Select Crash Avoidance Technologies

Objectives: Vehicle-based crash avoidance systems can potentially reduce crashes, but success depends on driver acceptance and understanding. This study gauged driver use, experience, and acceptance among early adopters of select technologies. Methods: Telephone interviews were conducted in early 2009 with 380 owners of Volvo vehicles equipped with forward collision warning with autobrake, lane departure warning, side-view assist, and/or active bi-xenon headlights and 485 owners of Infiniti vehicles with lane departure warning/prevention. Results: Most owners kept systems turned on most of the time, especially forward collision warning with autobrake and side-view assist. The exception was lane departure prevention; many owners were unaware they had it, and the system must be activated each time the vehicle is started. Most owners reported being safer with the technologies and would want them again on their next vehicles. Perceived false or unnecessary warnings were fairly common, particularly with side-view assist. Some systems were annoying, especially lane departure warning. Many owners reported safer driving behaviors such as greater use of turn signals (lane departure warning), increased following distance (forward collision warning), and checking side mirrors more frequently (side-view assist), but some reported driving faster at night (active headlights). Conclusions: Despite some unnecessary or annoying warnings, most Volvo and Infiniti owners use crash avoidance systems most of the time. Among early adopters, the first requirement of effective warning systems (that owners use the technology) seems largely met. Systems requiring activation by drivers for each trip are used less often. Owner experience with the latest technologies from other automobile manufacturers should be studied, as well as for vehicles on which technologies are standard (versus optional) equipment. The effectiveness of technologies in preventing and mitigating crashes and injuries, and user acceptance of interfaces, should be examined as more vehicles with advanced technologies penetrate the fleet.

Design and Evaluation of a Prototype Rear Obstacle Detection and Driver Warning System

This study, concerned with the development of driver interface criteria for a rear obstacle detection system, assessed the appropriateness of alternative warning timing algorithms and evaluated various interface approaches for presenting warning information to drivers. Interface testing used a minivan and a passenger sedan equipped with a prototype rear obstacle detection system. Two different warning timing algorithms and four different interface conditions were examined. The appropriateness of the warning timing algorithms was tested using an alerted backing procedure wherein drivers backed to known obstacles and braked in response to the warning. A surprise event scenario was also included in order to examine driver reaction to the warning under unexpected conditions. Alerted backing results suggest that although both timing algorithms led to few target strikes, one algorithm led to more acceptable ratings, fewer target strikes and close calls, and less urgent braking. None of the interface warning conditions reliably induced avoidance braking under the surprise event condition. Actual or potential applications of this work include the appropriate design of effective backing warning systems.

The Effects of Teen Passengers on Teen Driver Speeds and Headways

This observational study investigated teen driving as a function of passenger presence and passenger gender. Vehicles were observed leaving high school parking lots at dismissal time, and the apparent age (teen or adult) and gender of drivers and passengers were recorded. At sites near the school, vehicle speeds and headways were recorded using a LIDAR and video-based system. Vehicles in the traffic stream were matched, where possible, to vehicles identified leaving the school. Thus, vehicles driven by teens could be distinguished from “general traffic.” Passenger presence and gender had strong effects on speed and headway and were more pronounced than driver gender effects. While teens drove slightly faster than general traffic, the primary influence on speed was the presence of a male passenger. Similarly, shorter headways were associated with male, rather than female, passengers. Passenger influences on teen driving depend on passenger gender, driver gender, and the particular driving measure.

Perception of Approaching Motorcycles by Distracted Drivers May Depend on Auxiliary Lighting Treatments: A Field Experiment

A field experiment was conducted in daylight with 32 participants to determine whether left turning drivers’ gap acceptance in front of approaching motorcycles depends on the motorcycle’s forward lighting treatment. Five experimental lighting treatments including a modulated high beam headlamp, or the low beam headlamp plus pairs of low-mounted auxiliary lamps, high-mounted auxiliary lamps, both high- and low-mounted auxiliary lamps, or low-mounted LED lamps were compared to a baseline treatment with only the low beam headlamp illuminated. Participants viewed the approaching traffic stream (including the motorcycle) on an active roadway and indicated when it would be safe (and not safe) to initiate a left turn across the opposing lanes. Participants also shared their attention with a secondary visual distraction task that took their eyes off the forward roadway. Participants did not know that the purpose of the study was to measure their responses to approaching motorcycles. Based on participants’ indications of the last safe moment to turn, the mean temporal safety margin provided to the approaching motorcycle did not differ significantly between any of the experimental lighting treatments and the baseline treatment. However, having either low-mounted auxiliary lamps or modulated high beam lamps on the motorcycle significantly reduced the probability of obtaining a potentially unsafe short safety margin as compared to the baseline lighting treatment. Overall, the results suggest that enhancing the frontal conspicuity of motorcycles with lighting treatments beyond an illuminated low beam headlamp may be an effective countermeasure for daytime crashes involving right-of-way violations.

Visibility and Conspicuity of Detectable Warnings for Pedestrians with Visual Impairments

Detectable warnings are standardized tactile walking surfaces located at the end of curb ramps and train platforms to identify the potential hazard. A study was conducted to determine which detectable warning colors and patterns are visually detectable and conspicuous to pedestrians with visual impairments and to provide recommendations related to color, pattern, and contrast of detectable warnings for placement on sidewalks. Fifty individuals with low vision viewed each of 13 detectable warnings individually on four different types of simulated sidewalk. The set of detectable warnings included both solid colors and black-and-white patterns. The outcomes of interest were visual detection distance, participants’ descriptions of detectable warning colors, and participants’ ratings of each detectable warnings conspicuity against a particular simulated sidewalk. Detection distance results indicate that pedestrians with visual impairments were able to see most combinations of detectable warning and sidewalk from 8 ft away, but fewer were able to see them at greater distances. Detectable warnings that were similar in color to the sidewalk were seen by few participants, indicating that visual cues provided by the truncated-dome texture itself are not sufficient to ensure visual detection. The luminance contrast between the detectable warning and the sidewalk was an important factor for predicting the likelihood that a detectable warning would be seen. Besides luminance contrast, regression analyses indicated that some other characteristics of detectable warnings were generally associated with high detection rates and high conspicuity ratings, including color (reds and yellows rather than achromatic) and reflectance (lighter colors rather than darker colors). Additional recommendations for detectable warning visual characteristics are provided.

Effects of Multiple-Device Integration Strategies on Driver Comprehension of Crash Warnings

This experiment investigated the extent to which driver comprehension of imminent crash warnings is affected by the degree of integration when there are multiple Connected Vehicle products in the vehicle. Two displays were placed in an experimental vehicle: one representing original equipment and one representing a portable, nomadic device. Participants were randomly assigned to one of five device integration conditions. Participants drove on a test track and were occasionally presented with either a nonurgent message or an urgent crash warning. Participants recognized warnings most quickly when only one display was active in the car; when both displays were active, response times generally improved when messages and warnings were integrated into a single physical location. Warning recognition times were longer when a warning closely followed a non-urgent message on the other display than when a warning followed a non-urgent message on the same display. When messages and warnings from both source displays were integrated into a single display, this effect was not observed, suggesting that the separate display locations are responsible for the increased warning recognition time rather than the different formats of the messages from each source device.

A New Resource for Effective Consumer Product Instructions: Manufacturer's Guide to Developing Consumer Product Instructions:

This paper describes a new resource for developing and evaluating consumer product instructions. The U.S. Consumer Product Safety Commission (CPSC) staff, when conducting product safety assessments, often finds that the instructions provided with a product are deficient and result in consumers misassembling or misusing the product. Therefore, CPSC staff recently released the Manufacturers Guide to Developing Consumer Product Instructions. This Guide is unique in providing a relatively comprehensive, yet compact, set of principles specifically addressing the development and evaluation of instructional material for consumer products. It has a strong human factors orientation. The approach to developing the document was based upon the behavioral sequence that must be accomplished if the final outcome is to be a change in product user behavior. The content, structure, and perspective of the Guide make it useful for human factors professionals in product design, safety research, and forensics, as well as for developers of instructions and safety materials.