Has motorization in the U.S. peaked? Part 6: relationship between road transportation and economic activity

In the previous five reports in this series, I examined recent changes in the number of registered light-duty vehicles (cars, SUVs, pickups, and vans), and the corresponding changes in distance driven and fuel consumed. The units of the analyses were both the absolute numbers and the rates per person, per driver, per household, and (where appropriate) per vehicle. The main finding of those reports was that the respective rates all reached their maxima around 2004. I argued that, because the onsets of the reductions in these rates preceded the onset of the recession (in 2008), the reductions in these rates likely reflect fundamental, noneconomic changes in society. Therefore, these maxima have a reasonable chance of being long-term peaks as well. The present report examines the relationship between road transportation and economic activity since the end of the Second World War. The two measures of interest were distance driven by all vehicles per inflation-adjusted GDP and fuel consumed by all vehicles per inflation-adjusted GDP. The main finding is that distance driven per GDP reached its highest values in a broad plateau from the early 1970s through the early 1990s, and then decreased steadily. By 2012, the value of this measure decreased by 22% from its absolute maximum, which was reached in 1977. Some of the factors that likely contributed to the recent decline in the value of this measure are the decreased amount of personal transportation, decreased contribution to GDP of truck transportation, and the increased contribution to GDP of data services, information processing, and e-commerce. The amount of fuel consumed per GDP peaked in the early 1970s, and then decreased by 47% by 2012. The relatively steep decline in the value of this measure reflects the added contribution of the improvement in vehicle fuel economy from the 1970s on.The University of Michigan Sustainable Worldwide Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/110116/1/103145.pd

Has motorization in the U.S. peaked? Part 7: update through 2013

In Part 5 in this series of reports, I examined the changes from 1984 to 2012 in the number of registered light-duty vehicles, and the corresponding changes in distance driven and fuel consumed. The units of the analyses were both the absolute numbers and the rates per person, per driver, per household, and (where appropriate) per vehicle. The main finding of that report was that the respective rates all reached their maxima around 2004. I argued that, because the onsets of the reductions in these rates preceded the onset of the recession in 2008 by several years, the reductions in these rates likely reflect fundamental, noneconomic changes in society. Therefore, these maxima have a reasonable chance of being long-term peaks as well. The present report provides a brief update on these measures through 2013. The main findings are as follows: (1) Despite the population growth, the absolute amount of fuel consumed by light-duty vehicles decreased by 11% during the period 2004 (the year of maximum consumption) through 2013. (2) The reductions in the rates per person, per driver, per household, and (where appropriate) per vehicle from the corresponding maxima (around 2004) to 2013 were greatest for fuel consumed (averaging about 17%), followed by distance driven (about 8%) and number of vehicles (about 5%). (The fact that the reductions were greatest for fuel consumed reflects, in part, the added contribution of the improvements in vehicle fuel economy.) (3) The 2013 rates of vehicles and distance driven were comparable to the rates in the 1990s. The 2013 rates of fuel consumption were lower than the rates in 1984—the first year of this analysis. (4) There is no evidence in the 2013 data that the recent reductions in the rates were temporary. Indeed, out of the seven rates examined for number of vehicles and distance driven, four showed a decrease from 2012 to 2013 and three showed an increase. However, the changes in these rates were all within ±0.7%, suggesting that the situation in 2013 was generally the same as in 2012. (All four rates for fuel consumed decreased from 2012 to 2013, with the largest decrease of 1.1%.)The University of Michigan Sustainable Worldwide Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/110979/1/103186.pd

Energy intensities of flying and driving

Last year, I issued a report comparing energy intensities of flying and driving from 1970 through 2010. The main finding of that study was that, while flying domestically in the U.S. used to be much more energy intensive than driving, that is no longer the case. Indeed, in 2010—the last year examined in that study—the energy intensity of driving was 57% greater than the energy intensity of flying. The present study extends the analysis through 2012. Furthermore, this study corrects the publically available flying data for two inconsistencies: (1) the estimates of the energy intensity of flying are based on different carrier groups for fuel consumed and passenger miles flown, and (2) the estimates of the energy intensity of flying include cargo operations (paid freight and mail). The results indicate that, even before the corrections are made to the flying data, the energyintensity advantage of flying over driving has increased from 2010 to 2012. Furthermore, the net effect of the corrections to the flying data is that the advantage of flying has increased even further.The University of Michigan Sustainable Worldwide Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/111894/1/103194.pd

Commuting to work in the 30 largest U.S. cities

The aim of this study was to provide a broad overview of commuting by workers 16 years of age and older in the 30 largest U.S. cities, by highlighting the following aspects of commuting: who, how, how time consuming, and when. The study used the 2013 data from the American Community Survey—an ongoing annual survey by the U.S. Census Bureau. Below are the cities that were found to be on either extreme on several of the aspects examined: Median age: 34.4 years in Boston, 41.7 years in Louisville Males: 45.9% in Detroit, 56.2% in Houston No vehicle available: 1.8% in Fort Worth and San Jose, 46.0% in New York Working at home: 2.1% in Memphis, 7.1% in Austin and Portland Driving alone to work: 21.4% in New York, 82.9 in Louisville Carpooling to work: 4.9% in New York, 12.4% in Memphis Using public transportation to work: 0.7% in Oklahoma City, 56.7% in New York Walking to work: 1.2% in Fort Worth, 14.5% in Boston Bicycling to work: 0.1% in El Paso, 5.9% in Portland Mean travel time to work: 20.7 minutes in Oklahoma City, 39.7 minutes in New York Leaving for work between 5:00 am and 8:59 am: 59.8% in Detroit and Las Vegas, 73.5% in JacksonvilleSustainable Worldwide Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/112057/1/103196.pdfDescription of 103196.pdf : Final repor

Societal Violence, Driver Age, and Attained Education: Independent Contributions to Road Accidents?

Twenty years ago, an analysis (Sivak, 1983) showed that homicide rates and proportion of young drivers were significant and independent predictors of states’ fatal accident rates. In the present study, we revisited these relationships by examining the data for year 2000, and included attained education as an additional independent variable. The goal was to provide evidence concerning the degree of independent contribution of violence, driver age, and education to current accident patterns. A regression analysis was performed using the 2000 fatal accident data for the 50 individual states (excluding D.C.). The dependent variable was the fatal accident rate per licensed driver. There were three independent variables: the homicide rate per person, the proportion of licensed drivers under 20 years of age, and the proportion of persons that attained at least a college degree among the population aged 25 years and older. Consistent with Sivak (1983), both the homicide rate and the proportion of young drivers were significant predictors of states’ fatal accident rate, but so also was the proportion of college graduates. Specifically, a higher traffic fatality rate was associated with a higher homicide rate, a higher proportion of young drivers, and a lower proportion of college graduates. The respective simple correlation were 0.35, 0.50, and -0.66. A multiple regression showed that each of these three independent variables has a significant and independent relationship with the dependent variable. The three predictors accounted for a total of 63% of the variance in the traffic fatality rate. The present analysis indicates strong independent relationships between states’ homicide rate, proportion of young drivers, and attained education on one hand and states’ fatal accident rate on the other hand. However, because this was an observational study, causal relationships cannot be directly inferred. For example, from this multiple regression it is not possible to exclude the possibility that the apparent effects of the three independent variables stand for the effects of other, not explicitly identified variables. Nevertheless, the present results are consistent with the possibility of independent contributions to traffic accident causation of the level of societal violence, inexperience/risk taking of young drivers, and level of education. The presentation discusses the potential implication of these findings, along with methodological issues related to these kinds of analyses

Female drivers in the United States, 1963-2013: from a minority to a majority?

This study examined the changes in the relative proportions of male and female drivers in the United States from 1963 through 2013. The analysis used data from the Federal Highway Administration. During the period examined, the proportion of female drivers has gradually increased. In 1963, females represented 39.6% of all drivers. Females became a majority in 2005. In 2013, they constituted 50.5%. Although female drivers are currently a slight majority, the likelihood of them being on the road depends not only on their relative numbers, but also on the relative amount of driving that they do (with females driving less than males). A consideration of both the percentage of drivers by gender and the average annual distance driven by gender reveals that, in 1963, 23.8% of drivers on the road were females, which increased to 40.8% by 2013.The University of Michigan Sustainable Worldwide Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/111899/1/103195.pd

Analysis of performance ratings for tires

This study analyzed two sets of performance ratings for light-duty-vehicle tires. The aim was to ascertain whether some of the ratings in either set convey redundant information. The first set included the Uniform Tire Quality Grade (UTQG) ratings for 2,734 tires, published by the U.S. National Highway Traffic Safety Administration. The second set consisted of ratings for 49 tires published by Consumer Reports. The approach consisted of using factor analysis to determine whether the number of variables in the two sets (3 in UTQG, and 11 in Consumer Reports) can be reduced to a smaller number of independent factors. The results indicate that the three UTQG variables form two factors. The first is dominated by tread properties, while the second factor reflects tread-abrasion resistance. The two factors accounted for 83% of the variance. The 11 Consumer Reports variables form four factors. These factors are dominated, in turn, by tread properties, the tire (and especially belt) construction, tread-band flexibility (particularly in the longitudinal direction), and tread-abrasion resistance. Each of the 11 variables loaded highly on at least one factor. The four factors accounted for 68% of the variance. The examination of the factors in each analysis suggests that each factor that is highly loaded by more than one variable represents richer and more complex information than what smaller subsets of variables could capture. Therefore, none of the variables could be excluded if one wants to provide the same information conveyed by the full sets of the variables.The University of Michigan Sustainable Worldwide Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/90513/1/102852.pd

Optimal control of transitions between nonequilibrium steady states

Biological systems fundamentally exist out of equilibrium in order to preserve organized structures and processes. Many changing cellular conditions can be represented as transitions between nonequilibrium steady states, and organisms have an interest in optimizing such transitions. Using the Hatano-Sasa Y-value, we extend a recently developed geometrical framework for determining optimal protocols so that it can be applied to systems driven from nonequilibrium steady states. We calculate and numerically verify optimal protocols for a colloidal particle dragged through solution by a translating optical trap with two controllable parameters. We offer experimental predictions, specifically that optimal protocols are significantly less costly than naive ones. Optimal protocols similar to these may ultimately point to design principles for biological energy transduction systems and guide the design of artificial molecular machines.Comment: Accepted for publication at PLoS ON

Public opinion about self-driving vehicles in China, India, Japan, the U.S., the U.K., and Australia

This report documents a new study of public opinion about self-driving vehicles in China, India, and Japan. The survey yielded completed responses from 610 respondents in China, 527 respondents in India, and 585 respondents in Japan. For comparison, the report also includes recently released findings from the same survey in the U.S., the U.K., and Australia. The main findings (applicable to each of the six countries) are as follows: The majority of respondents had previously heard of autonomous or self-driving vehicles, had a positive initial opinion of the technology (or neutral in the case of Japan), and had high expectations about the benefits of the technology. However, the majority of respondents expressed high levels of concern about riding in selfdriving vehicles, safety issues related to equipment or system failure, and self-driving vehicles not performing as well as human drivers. Respondents also expressed high levels of concern about vehicles without driver controls; selfdriving vehicles moving while unoccupied; and self-driving commercial vehicles, buses, and taxis. The majority of respondents expressed a desire to have this technology in their vehicles. However, a majority was also unwilling to pay extra for the technology (except for respondents in China and India). In comparison to the respondents in the U.S., the U.K., and Australia, respondents in China and India had more positive initial opinions of self-driving vehicles, expressed greater interest in having such technology on their personal vehicles, and were willing to pay the most for it. Japanese respondents, on the other hand, generally had more neutral initial opinions about self-driving technology and were willing to pay the least for it. The main implications of these results are that the respondents in the six countries surveyed, while expressing high levels of concern about riding in vehicles equipped with this technology, mostly feel positive about self-driving vehicles, have optimistic expectations of the benefits, and generally desire self-driving-vehicle technology (though a majority in four out of the six countries surveyed are not willing to pay extra for such technology at this time).The University of Michigan Sustainable Worldwide Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/109433/1/103139.pd

Road-safety management in Brazil, Russia, India, and China

This study examined road-safety management in Brazil, Russia, India, and China (the BRIC countries). The main topics reviewed were recent crash statistics, key governmental agencies in charge of road safety, road-safety programs, influential organizations outside of the government, key research institutes, and major barriers to improvement. The main findings are as follows: (1) Each BRIC country has governmental organizations with responsibilities for road safety. However, none of these countries has a single lead governmental unit responsible for national road safety. (2) The Russian Federation has a strategic road-safety plan, including a specific target for reduction of road fatalities. The strategic safety plan of China is limited to certain types of roads, and it aims to reduce fatality rates per vehicle. In Brazil and India, there is not yet any road-safety plan or road-safety targets. (3) There are several non-governmental organizations involved in road-safety work in Brazil, the Russian Federation, and India, but not in China. (4) Road-safety research is conducted in each of the four countries. (5) All four countries have recently introduced several new road-safety interventions. However, the introduced interventions are not based on a systems approach that would involve comprehensive measures supporting each other, or they are not applied uniformly throughout the country.The University of Michigan Sustainable Worldwide Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/89427/1/102786.pd