Brandon Schoettle

Recent Changes in the Age Composition of Drivers in 15 Countries

Objective: This study examined the recent changes in the percentage of persons with a drivers 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 drivers license, and an increase in the percentage of older people with a drivers license. In the other pattern (observed for the other 7 countries), there was an increase in the percentage of people with a drivers 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.

Update: Percentage of Young Persons With a Driver's License Continues to Drop

In two previous studies, we have shown that in several countries, including the United States, the percentage of young persons with a drivers 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 drivers license in 1983, 2008, and 2010 were 87.3, 75.5, and 69.5, respectively.

Recent changes in the age composition of U.S. drivers : implications for the extent, safety, and environmental consequences of personal transportation.

Objective: This study examined the changes in the United States from 1983 to 2008 in the percentage of persons with drivers licenses as a function of age. Method: The analysis used data from the Federal Highway Administration on drivers licenses by age. Results: (1) Over the past 25 years, there was a substantial decrease in the percentage of young people with a drivers license and a substantial increase in the percentage of older people with a drivers license. (2) For cohorts who were between age 20 and 44 in 1983 (and thus between age 45 and 69 in 2008), the percentage of licensed drivers has not changed appreciably between 1983 and 2008. This finding suggests that, for all practical purposes, all those who wanted to obtain a drivers license did so by age 20. (3) For cohorts who were between age 45 and 59 in 1983 (and thus between age 70 and 84 in 2008), this percentage dropped substantially. This finding reflects the surrendering of drivers licenses with advanced age. Conclusion: The age composition of US drivers has changed substantially between 1983 and 2008. In 1983, the largest group of drivers included those between 25 and 29 years of age. In contrast, in 2008, the largest group included those 70 years and older.

High-Beam and Low-Beam Headlighting Patterns in the U.S. and Europe at the Turn of the Millennium

This study was designed to provide photometric information about current U.S. and European high- and low-beam headlamps. The sample included 20 headlamps manufactured for use on the 20 best-selling passenger vehicles for model year 2000 in the U.S., and 20 headlamps manufactured for use on the 20 best-selling passenger vehicles for model year 2000 in Europe. The vehicles sampled represent 49% and 47%, respectively, of all vehicles sold in the U.S. and in Europe. The lamps were purchased directly from vehicle dealerships. The photometric information for each lamp was weighted by the sales figures for the corresponding vehicle. The results are presented both in tabular form for the 25th-percentile, the median (50th-percentile), and the 75th-percentile luminous intensities, as well as in graphical form (for the median luminous intensities), both for high- and low-beam headlamps (from 45 deg left to 45 deg right, and from 5 deg down to 7 deg up).

Toward Understanding the Recent Large Reductions in U.S. Road Fatalities

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.

The Reasons for the Recent Decline in Young Driver Licensing in the United States

Objective: This survey examined why a substantial percentage of young adults currently do not have a drivers license and the future plans of this group concerning obtaining a license. Method: A questionnaire was developed to examine several issues related to an individuals decision not to obtain a drivers license. An online survey was conducted, yielding useable responses from 618 persons aged 18 to 39 without a drivers license. Results: The top 8 reasons for not having a drivers license were as follows: (1) too busy or not enough time to get a drivers 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 drivers license. On the other hand, 69% expect to get a drivers license within the next 5 years. Young adults without a drivers 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.

Survival in Fatal Road Crashes: Body Mass Index, Gender, and Safety Belt Use

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.

Driving with HID Headlamps: A Review of Research Findings

High-intensity discharge (HID) headlamps have several advantages over tungsten-halogen headlamps which includes greater light efficiency (limens per watt) and a longer service life. However, a safety point of view, the main attraction of HID headlamps is that since they produce more light they have the potential to provide more useful illumination for the driver. But, at the same time, there are safety concerns with the effects of HID illumination on perception of the colors of important objects and glare to oncoming traffic. This paper will review research evidence that has been accumulated over the past 14 years concerning the potential benefits and drawbacks associated with the use of HID headlamps. The paper will conclude that the evidence strongly supports the use of well-designed HID headlamps.

Performance of the First Generation of HID Headlamps in the U.S.

Abstract This analytical study compared the median beam pattern of a sample of 19 HID low beams manufactured for model year 2000 vehicles sold in the U.S., with a market-weighted median beam pattern of tungsten-halogen lamps for vehicles of the same model year. The results indicate that the HID lamps tended to provide wider beam patterns than did the tungsten-halogen lamps, which, in turn, should improve the visibility of pedestrians on curves and may make the lane-maintenance task less demanding. On right curves, there was an increase in potential glare towards oncoming drivers, while on left curves there was a decrease in glare potential. On straight roads, the HID lamps produced more illumination for pedestrians and road delineation on the left side of the road. This was also the case for the right side of the road, but only for the projector HID lamps; the nonprojector HID lamps produced less illumination at the relevant locations than did the tungsten-halogen lamps. Finally, on straight roads HID lamps produced less glare illumination for oncoming drivers than did the tungsten-halogen lamps. The results for traffic-sign illumination varied with the location of the sign. HID lamps produce more light than do tungsten-halogen lamps. Consequently, they hold great promise for improving the nighttime safety of driving by improving the low-beam light distribution. The present analysis indicates that this promise has already been partially met in the first generation of HID lamps on vehicles in the U.S.

LED headlamps: Glare and colour rendering

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.