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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]

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.