The AAA Foundation for Traffic Safety is dedicated to saving lives through research and education. Fundamental to the research that we perform is the ability to quantify traffic risks. Quantifying traffic risks requires data regarding not only the motor vehicle crashes that occur and the number of people who are involved, injured, and killed in crashes, but also data regarding to people’s exposure to risk, such as the number of miles that they travel. To address the need for current data regarding driving exposure in relation to driver, vehicle, and trip characteristics, the AAA Foundation commissioned researchers at the Urban Institute to perform a develop and implement a data collection system to collect national-level data on the driving of the American public. The data collection system, the American Driving Survey, consists of daily telephone interviews of a representative sample of the United States population, conducted in both English and Spanish by both landline and cellular phone, in which respondents aged 16 years or older are asked to report all of the driving that they did over a 24-hour period the day before the interview. By aggregating results from interviews conducted each day, the data are used to estimate the average and total amount that Americans drive each year and to describe the driving that they do. This data collection system–the American Driving Survey–was launched in May of 2013, and results of the first full one-year period of data collection were published by the AAA Foundation in the report American Driving Survey: Methodology and Year 1 Results, May 2013 — May 2014 (AAA Foundation, 2015). This report presents survey results regarding the driving of the American public in calendar years 2014 and 2015. Across these two calendar years, interviews were completed with representatives of 7,576 households, and detailed information about daily driving trips was collected from a sample of 5,774 drivers. Year-over-year changes are shown for aggregate national statistics only, because the survey sample is not large enough to produce statistically reliable estimates of year-over-year changes in driving for most subgroups. Results for specific demographic groups are shown for both years combined to improve the stability and precision of the estimates. In 2014 and 2015, an average of 87.5% of US residents aged 16 and older reported that they drove at least occasionally. These drivers reported spending an average of 47.1 minutes driving and drive an average of 29.8 miles daily, or 294 hours and 10,874 miles annually. However, on any given day, roughly one-third of drivers did not do any driving. Drivers reported spending an average of 68.4 minutes driving and driving an average of 43.2 miles on days when they drove. On average, men were slightly more likely than women to drive at all, and men reported driving longer distances on average than women, but women reported a greater average daily number of driving trips than did men. People aged 30-49 were the most likely to be drivers, and drivers aged 30-49 made more trips and drove longer distances, on average, than did younger or older drivers. College graduates were more likely to be drivers than were respondents with lower levels of education, and college graduates made more driving trips and drove longer distances on average than did drivers with lower levels of education. Drivers who described the area where they live as a town or city reported making more driving trips each day than did drivers who reported that they live in the country; however, drivers who lived in the country reported driving more miles daily than did drivers who lived in towns or cities. Fewer drivers drove on weekends than on weekdays; however, drivers who did drive on the weekend drove more miles, on average, than drivers who drove on weekdays, with the net result being that similar numbers of total miles were driven on an average weekend day and on an average weekday. Fewer drivers drove on any given day in the winter than in the spring, summer, or fall; and drivers tended to drive fewer miles on days when they drove in the winter than in other seasons. Differences between driving in the spring, summer, and fall were minimal. The majority of all driving (66.2% of total trips and 61.9% of total miles driven) is done by solo drivers with no passengers. While both men and women did more of their driving alone than with passengers, a larger share of women’s driving than men’s driving included passengers. Drivers aged 65 and older did a greater share of their driving with passengers compared with younger drivers. At the household-level, the average number of drivers per household was 1.8, and the average number of vehicles per household was 2.1. Most households (58.0%) reported having the same number of vehicles as drivers, 14.0% reported having fewer vehicles than drivers, and 27.9% reported having more vehicles than drivers. Households in the Northeast were the most likely to have fewer vehicles than drivers and the least likely to have more vehicles than drivers. Households self-described by respondents as being in the country were more likely than households in towns or cities to have more vehicles than drivers; households described as being in cities were more likely than households in towns or in the country to have fewer vehicles than drivers. Approximately 7.4% of households reported that they had no vehicles. While the overwhelming majority of drivers live in households with at least one vehicle and most households with no vehicles also have no drivers, nearly 1 in 5 people who live in zerovehicle households reported that they drive at least occasionally, and roughly 1 in 7 drivers living in a zero-vehicle households (or roughly 2.8% of all people in zero-vehicle households) reported driving on any given day. All metrics of driving increased slightly from 2014 to 2015. This survey estimates that the percentage of the population that drives increased from 87.3% in 2014 to 87.8% in 2015. In addition, data from the US Census Bureau indicates that the driving-aged population of the United States increased by approximately 1.0% from 2014 to 2015. As a result, the number of drivers in the United States increased by approximately 3.3 million, or 1.5%, from 2014 to 2015. Furthermore, the amount that drivers reported driving each day increased very slightly, from 29.7 miles per day in 2014 to 29.9 miles per day in 2015. This survey estimates that the total number of miles driven by Americans increased by approximately 2.4%, from approximately 2.40 trillion miles in 2014 to 2.45 trillion miles in 2015. The remainder of this report explores the findings summarized above in more detail, and also provides a comprehensive description of the survey methodology. (Author/publisher)
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