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This simulation study examined the effects of proportional increases in light output throughout the entire headlamp beam pattern on visibility. The baseline beam pattern was a median market-weighted US tungsten–halogen low-beam pattern. Ten derived beam patterns were obtained by multiplying each point in the baseline beam pattern by a constant that ranged from 1.1 to 2.0, in increments of 0.1. Finally, for comparison, we also used the median market-weighted US high-beam pattern. Visibility changes were estimated by calculating the change in the reach of a 3-lux line 0.25 m above the road surface, for both straight and curved roadways. The results indicate that substantial gains in visibility on straight roadways require an increase of about 50% in the overall light output of low beams. On curves, obtaining a substantial gain in visibility in several lateral positions would require significantly greater increase in light output. These results provide an enhanced baseline against which to compare other potential improvements in low-beam visibility, including more localized changes in static beam patterns and adaptive headlighting systems. [ABSTRACT FROM AUTHOR]

This study examined the potential effects of the spectral power distributions of mercury-free high-intensity discharge (HID) headlamps on discomfort glare for oncoming drivers and on colour rendering of retroreflective traffic materials. In both cases, the effects of mercury-free HID light sources were compared to the changes in these properties that occurred when the tungsten–halogen light sources were replaced with traditional (mercury containing) HID light sources. Specifically, the effect on discomfort glare was estimated by comparing the chromaticities of nine mercury-free light sources with the chromaticities of 17 traditional HID light sources. Similarly, the effects on colour rendering were estimated by comparing the chromaticities of seven red retroreflective materials (red being the most important messenger of meaning in traffic control) when illuminated by the mercury-free light sources with the chromaticities of the same materials when illuminated by the traditional HID light sources. The main findings are: (1) The discomfort glare from the mercury-free HIDs is predicted to be comparable to that from the 'bluest' of the traditional HIDs. (2) Colour rendering with headlamps using the mercury-free HIDs is likely to be acceptable. (3) The use of mercury-free HIDs is unlikely to have appreciable effects on the relative brightness of coloured retroreflective materials. [ABSTRACT FROM AUTHOR]

Because of rapid improvements in the light output of light-emitting diodes (LEDs), serious consideration is being given to using LEDs as light sources for headlamps. This analytical study examined the potential effects of LEDs on discomfort glare for oncoming drivers and on colour rendering of retroreflective traffic materials. In both cases, the effects of LED light sources were compared to the changes in these properties that occurred when the traditional tungsten halogen light sources were replaced with high-intensity discharge (HID) light sources. Specifically, the effect on discomfort glare was estimated by comparing the chromaticities of seven LED light sources (considered for use in headlamps) with the chromaticities of the light sources from 17 actual HID headlamps. Analogously, the effects on colour rendering were estimated by comparing the chromaticities of seven red retroreflective materials (red being the most important messenger of meaning in traffic control) when illuminated by the LED light sources with the chromaticities of the same materials when illuminated by the HID light sources. Based on our analyses, headlamps using the currently considered range of LEDs are predicted to result in: 1) more discomfort glare than the current HID headlamps, and substantially more discomfort than tungsten halogen headlamps; 2) acceptable colour rendering; and 3) no appreciable effects on the relative brightness of red retroreflective materials. [ABSTRACT FROM AUTHOR]

This study was designed to compare the illuminated surface areas of high-intensity discharge (HID) and tungsten halogen low-beam headlamps in the USA. A sample of 20 tungsten halogen lamps and 17 HID lamps for model year 2000 vehicles in the US was examined. The illuminated surface area was determined using a modified version of an Economic Commission for Europe (ECE) method for evaluating the illuminated surface of signalling devices. The main finding is that the HID low (passing) beams generally have smaller illuminated surface areas than do the tungsten halogen low beams. Because smaller light sources result in more discomfort glare (presumably via greater luminance), the present finding suggests that the smaller illuminated area is one reason for drivers reporting more discomfort from HID lamps. An implication is that the increased discomfort from HID lamps could be reduced by increasing their illuminated surface area. [ABSTRACT FROM AUTHOR]

This in-traffic study evaluated driving performance with and preference for high-intensity discharge (HID) low beam headlamps. Subjects drove two identical luxury sedans. One vehicle was equipped with HID low beams and the other with tungsten halogen low beams. The main difference between the two beams was that the HID lamps provided more spread light. Driving performance was evaluated by analysing steering frequencies. The hypothesis was that the wider beam pattern of the HID lamps would be beneficial by reducing the steering effort in the 0.3-0.6 Hz range, which has been used in previous studies as an index of steering-task difficulty. The main finding is that the wider HID beam pattern made lane maintenance less demanding, as measured by a reduction in the steering frequencies between 0.3 and 0.6 Hz. The implication is that HID headlamps may be beneficial to safety, because their wider beam pattern allows more of the limited information processing resources of drivers to be allocated to other tasks. When the subjects were not primed before driving to pay attention to the headlamps, they did not show, as a group, preference for either type of lamp. However, when they were told to pay attention to the headlamps, they overwhelmingly preferred the HID lamps. [ABSTRACT FROM AUTHOR]

Previous research has shown that, as expected, fast-rise signals (such as LEDs and neon lamps) lead to shorter reaction time than that obtained with slower-rise signals (such as incandescent lamps). This study, in two converging experiments, investigated whether rapid rise time makes turn signals more resistant to masking from an adjacent headlamp. The first experiment used a method of limits to obtain luminous intensity thresholds for LED and incandescent turn signals in the presence of headlamp glare. In the second experiment, subjects judged the relative conspicuity of simultaneously presented LED and incandescent turn signals when they flanked an illuminated headlamp. The results of the two experiments were consistent: there was no difference between the two light sources in either detection threshold or judged conspicuity. These results suggest that faster rise time does not affect the resistance of turn signals to headlamp masking. [ABSTRACT FROM AUTHOR]

This study measured direct and rearview-mirror glare illuminances produced by low-beam headlamps in a sample of 22 passenger vehicles. The glare illuminances were measured for 12 common glare situations that were defined by a full factorial combination of three scenarios (oncoming driver, center rearview mirror of a preceding driver, or driver-side mirror of a preceding driver one lane to the right), two longitudinal distances (25 m or 50 m), and two vertical locations (illuminated vehicle being either a car or a light truck/van/sport utility vehicle). The measurements were made outdoors at night on asphalt pavement. The median illuminances (not taking into account window transmittance or mirror reflectance) ranged from 0.5 lux for an oncoming driver of a light truck/van/sport utility vehicle at a distance of 50 m, to 3.4 lux at the driver-side mirror of a preceding car at 25 m one lane to the right. The ratios of the maxima and the minima measured for each of the 12 glare situations were large, ranging from about 5:1 to 36:1. The median actual illuminances were compared to the median expected illuminances based on a recent, laboratory-measured, representative sample of US low-beam patterns, taking into account the possible effects of dirt, voltage, misaim, and pavement reflectance. This analysis indicates that the actual illuminances could be very well modeled using the laboratory-measured beam patterns and assuming a linear relationship between the light output of clean and dirty headlamps. Additional analyses evaluated the relationships between headlamp mounting height and glare illuminance. [ABSTRACT FROM AUTHOR]

Previous studies have shown that the visibility of a front turn signal is decreased if a headlamp is located near the turn signal. Consequently, both the US and ECE regulations require the turn signals to be more intense in such situations. However, it is unclear how adjacent light sources affect suprathreshold aspects, such as conspicuity. The present field study was designed to examine the effects of several factors on the night-time conspicuity of front turn signals. Specifically of interest were the effects of the number, luminous intensity, and spatial arrangement (including spacing) of the potentially interfering lamps. The following are the main findings: (1) The conspicuity of a turn signal was significantly lower when it was separated from a 1000 cd low-beam headlamp by 50 mm rather than 100 mm (centre-to-edge). A 200 cd turn signal at 100 mm was equal in conspicuity to a 288 cd turn signal at 50 mm. This effect is smaller than the effects obtained in previous studies using threshold-visibility paradigms. (2) Adding a second masking light source, at the same 50-mm spacing as the first masking light source, significantly influenced the conspicuity of the turn signal. The effect of the second masking source can be compensated for by an increase in the turn signal intensity corresponding to 8.5% of the intensity of the second masking source. (3) The conspicuity of the turn signal was unaffected by the spatial arrangement of two masking light sources. [ABSTRACT FROM AUTHOR]

Objective: This survey examined why a substantial percentage of young adults currently do not have a driver's license and the future plans of this group concerning obtaining a license., Method: A questionnaire was developed to examine several issues related to an individual's decision not to obtain a driver's license. An online survey was conducted, yielding useable responses from 618 persons aged 18 to 39 without a driver's license., Results: The top 8 reasons for not having a driver's license were as follows: (1) too busy or not enough time to get a driver's license (determined by personal priorities), (2) owning and maintaining a vehicle is too expensive, (3) able to get transportation from others, (4) prefer to bike or walk, (5) prefer to use public transportation, (6) concerned about how driving impacts the environment, (7) able to communicate and/or conduct business online instead, and (8) disability/medical/vision problems. Of the respondents, 22% indicated that they plan to never obtain a driver's license. On the other hand, 69% expect to get a driver's license within the next 5 years. Young adults without a driver's license-in comparison with the general population of the same age-tend to have less education and higher unemployment. However, the present study was not designed to investigate whether there is a causal relationship or the direction of the effect if there were such a relationship.

In two previous studies, we have shown that in several countries, including the United States, the percentage of young persons with a driver's license has recently decreased substantially. In this update, we extend the analysis for the United States--originally performed for 1983 and 2008-through 2010 by using driver-license and general-population data from the Federal Highway Administration and the U.S. Census Bureau. The results indicate that the general trend continues. For example, the percentages of persons 19 years of age with a driver's license in 1983, 2008, and 2010 were 87.3, 75.5, and 69.5, respectively.

Objective: This study examined recent trends in gender differences in the percentage of persons with driver's licenses as a function of age by comparing data from 2010 and 1995., Method: The analysis used data from the Federal Highway Administration and the U.S. Census Bureau., Results: There are 2 main findings. First, the percentage of males with a driver's license decreased from 1995 to 2010 for those younger than 60; for females a decrease occurred for those younger than 50. Second, in 2010, proportionally more males younger than 45 had a driver's license than was the case for females; the opposite relationship held for persons 45 and older., Conclusions: The observed gender trends in driver licensing will likely have major implications on the extent and nature of vehicle demand, energy consumption, and road safety.

Objective: This study examined the recent changes in the percentage of persons with a driver's license in 15 countries as a function of age., Method: The countries included were Canada, Finland, Germany, Great Britain, Israel, Japan, Latvia, The Netherlands, Norway, Poland, South Korea, Spain, Sweden, Switzerland, and the United States., Results: The results indicate 2 patterns of change over time. In one pattern (observed for 8 countries), there was a decrease in the percentage of young people with a driver's license, and an increase in the percentage of older people with a driver's license. In the other pattern (observed for the other 7 countries), there was an increase in the percentage of people with a driver's license in all age categories. A regression analysis was performed on the data for young drivers in the 15 countries to explore the relationship between licensing and a variety of societal parameters. Of particular note was the finding that a higher proportion of Internet users was associated with a lower licensure rate., Implications: The results of the analysis are consistent with the hypothesis that access to virtual contact reduces the need for actual contact among young people., (Copyright © 2012 Taylor & Francis Group, LLC)

Objective: This study examined gender effects in six geometric scenarios of 2-vehicle crashes in which an involved driver could potentially ascertain the gender of the other driver prior to the crash., Method: The actual frequencies of different combinations of the involved male and female drivers in these crash scenarios were compared with the expected frequencies if there were no gender interactions. The expected frequencies were based on annual distance driven for personal travel by male and female drivers., Results: The results indicate that in certain crash scenarios, male-to-male crashes tend to be underrepresented and female-to-female crashes tend to be overrepresented., Conclusions: The obtained pattern of results could be due to either differential gender exposure to the different scenarios, differential gender capabilities to handle specific scenarios, or differential gender expectations of actions by other drivers based on their gender. The current lack of information on gender exposure in different scenarios, scenario-specific driver skills, and driver expectations based on other drivers' gender prevents ruling out any of these possible explanations.

Objective: This study was designed to investigate the relationship between the involvement of out-of-state drivers in fatal crashes and each US state's fatality rate per distance driven., Method: Two analyses were performed. In the first analysis, we examined the percentages of out-of-state drivers among those involved in fatal crashes using the data from the Fatal Analysis Reporting System (FARS). In the second analysis, we correlated these percentages with the states' fatality rates per distance driven. Both analyses used the data for 2008., Results: There are two main findings of this study. First, there is wide variability across the 50 states in the percentage of all drivers involved in fatal crashes who were out-of-state drivers, with a minimum of 5.0 percent in California and a maximum of 41.2 percent in Wyoming. Second, there is a positive correlation between this percentage and the corresponding fatality rate per distance driven., Conclusions: There are two main findings. First, states vary greatly in terms of the involvement of out-of-state drivers in fatal crashes. Second, the states with higher fatality rates tend to have higher percentages of out-of-state drivers among the persons involved in fatal crashes. However, whether this relationship is causative (ie, the extent of the involvement of out-of-state drivers among the persons involved in fatal crashes influences the states' overall fatality rates) or noncausative (eg, there is more out-of-state traffic in states with higher fatality rates) cannot be ascertained from the available data. The missing data concern the relative distance driven in each state by out-of-state drivers.

Background: From 2005 to 2009, U.S. road fatalities dropped by 22 percent (from 43,510 to 33,963). A reduction of such magnitude over such a short time has not occurred since road safety statistics were first kept (starting in 1913), except for the reductions during World War II., Objective: The study was performed to contribute to our understanding about the mechanisms that could be responsible for this unprecedented drop in road fatalities by analyzing the detailed information from the Fatality Analysis Reporting System (FARS)-a census of all U.S. crashes that involve a fatality., Method: The study compared the data for 2005 (the recent peak year in terms of road fatalities) with the data for 2008 (the latest year for which detailed data are available). The focus was on identifying those conditions that showed the largest reductions and those that showed the smallest reductions (or increases of any magnitude). The analysis involved an examination of the variables in the FARS database, which is divided into accident, vehicle, driver, occupant, and nonmotorist subsets., Results: The report highlights the most interesting patterns of changes for 19 variables.

Background: This study evaluated the associations of body mass index (BMI), gender, and use of safety belts with the survival of drivers involved in fatal road crashes., Method: The census data of all U.S. fatal crashes that did not involve pedestrians, bicyclists, or motorcyclists were examined for an 11-year period., Results: If involved in a crash with one or more fatalities, the odds of female drivers being among the fatalities are 1.28 times higher than those of male drivers, and the odds of unbelted drivers being among the fatalities are 5.43 times higher than those of belted drivers. The relationship of survivability to BMI depends on the gender and safety belt use of the driver., Conclusions: For male drivers, increased BMI appears beneficial when safety belts are used but detrimental when not used. For belted female drivers, normal BMI is associated with the lowest odds of being killed, and both increased and decreased BMIs increase the odds. For unbelted female drivers, no reliable trends were present among the BMI categories.

Introduction: This exploratory study investigated the relationship between vision obstructions from body pillars and lane-change crashes., Methods: The vision obstructions were quantified by measuring, from the driver's perspective, the horizontal angular sizes and locations of the driver-side A-, B-, and C-pillars. The sample consisted of 21 vehicle models, including 13 passenger cars, 6 SUVs, 1 minivan, and 1 pickup truck. To control for driver differences, going-straight crashes were used for comparison, with the dependent variable being the ratio of lane-change crashes to going-straight crashes. The analysis used North Carolina crash data., Results: The results of a multiple regression indicate that the relative frequency of lane-change crashes tended to increase with both wider A-pillars and with A-pillars located farther away from straight ahead., Impact on Industry: The finding supports the hypothesis that visibility obstructions due to A-pillars have safety implications.

The influence of lateral visibility from the vehicle cabin on safety was evaluated by examining the differences in lane-change crashes of four-door and two-door body styles of the same vehicle models. These two vehicle styles were used because B-pillars (the pillars between the front and rear seats) on four-door models are farther forward, and thus nearer the fore-aft position of the driver. (Furthermore, the B-pillars on two-door models can be narrower, and some two-door models have no B-pillars at all.) To control for driver differences between these two body styles, going-straight-ahead crashes were used for comparison. The analysis used 2000-2003 North Carolina crash data, and considered the crash experience of four-door and two-door body styles for the same 10 vehicles for model years 1995 and newer. The main finding is that four-door body styles are more likely to be involved in lane-change crashes than are two-door body styles of the same vehicle models. This finding suggests that lateral visibility out of the vehicle cabin affects safety.

Problem: Conventional low beams headlamps do not provide sufficient illumination for nighttime visibility on curves., Method: This analytical study evaluated the advantages and disadvantages of several curve-lighting strategies that involve moving one or both low beams by various amounts. Two curve radii were examined for both curve directions, using representative tungsten-halogen and high-intensity discharge low-beam patterns. The dependent variable was the maximum distance of 3-lux illumination (combined from both lamps) at a plane 0.25 m above the roadway for seven lateral positions., Results: For short-radius, left and right curves, moving both lamps in parallel should substantially increase the visibility of objects in one's lane of travel, in several additional lanes of travel to the left and right, and off the road., Discussion: Because of the lateral trade-offs of advantages and disadvantages for large-radius curves, additional research is needed to better understand the desirable approach for these types of curves., Impact on Industry: Moving both lamps in parallel into the curve is recommended for small-radius curves.

The purpose of this qualitative research was to explore the effect that current nursing attire has on the image of the nursing profession. A number of nurses and a nonnurse were interviewed to determine how attire affected their perception of today's nurses. The two research questions were as follows: (1) is the changing dress of nurses projecting a negative image to the public? and (2) What components of a nurse's apparel indicate professionalism? Content analysis was performed on transcriptions from the tape-recorded responses of a purposeful sample of health care workers: 12 registered nurses, 1 bachelor of nursing student, and 1 layperson. The responses for the first research question were not directly addressed by the participants. However, one overall theme emerged, which was labeled "I can't tell you what it is, but I know it when I see it." The main theme that emerged for the second research question was labeled "total package," with role identification and competency being related themes. As a result of this research, nursing administrators and other health care professionals could gain an understanding of the importance of nursing attire as an indicator of nursing professionalism. Future research needs to examine the same research questions with health care consumers in a variety of acute and community-based health care settings.