Transportation safety in the United States

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Annual US vehicle miles traveled (blue, in tens of billions) and traffic fatalities per billion miles traveled (red) from 1921 to 2015.

Transportation safety encompasses automobile accidents, airplane crashes, railroad and motorcoach fatalities and maimings, and other mass transit incidents.

The U.S. government's National Center for Health Statistics reported 33,736 motor vehicle traffic deaths in 2014. This exceeded the number of firearm deaths which was 33,599 in 2014.[1] According to another U.S. government office, the National Highway Traffic Safety Administration, motor vehicle crashes on U.S. roadways claimed 32,744 lives in 2014 and 35,092 in 2015.[2] (The National Center for Health Statistics may have different criteria for inclusion and/or a slightly different methodology from the National Highway Traffic Safety Administration.) The National Highway Traffic Safety Administration report comparing 2015 to 2014 noted that fatalities increased from 2014 to 2015 in almost all segments of the population—passenger vehicle occupants, passengers of large trucks, pedestrians, pedalcyclists (commonly referred to as cyclists), motorcyclists, alcohol-impaired driving fatalities, male/female, daytime/nighttime. Fatalities of drivers of large trucks remained unchanged. The National Highway Traffic Safety Administration performed a regression analysis between monthly roadway fatalities and various possible explanatory variables over the five year period 2011–2015. As one might expect, the strongest correlation was with Vehicle Miles Traveled (VMT), which had a correlation of .80, followed by average monthly temperature, which had a correlation of .74, meaning that higher temperatures were associated with increased fatalities.[3] Part of the reason for that pattern may be that more people are out walking and biking in the warmer months, and pedestrians and cyclists are often victims of collisions with motor vehicles. The report also suggests that there may be more vacation travel during warmer months. (It is not stated whether the analysis used Annual Vehicle Miles Traveled or Monthly Vehicle Miles Traveled.) Although not mentioned, motorcycle use, and therefore motorcyclist fatalities, may also increase in warmer months.

The National Safety Council, a nonprofit safety advocacy group, estimates U.S. motor vehicle deaths in 2016 were 40,200, a 14 percent increase from its 2014 estimate. The National Safety Council measures roadside deaths differently than U.S. government agencies. The National Safety Council counts traffic and non-traffic deaths within one year of an accident while the government counts only traffic deaths occurring within 30 days of a crash. The National Safety Council's statistics show that the increase in 2016 was due only in part to increased miles driven (due to population growth, low gasoline prices, and a strengthening economy.) The National Safety Council suggests the increase in deaths not explained by increased vehicle miles is attributable to complacency about impaired driving and increased driver distraction.[4]

Motor vehicle deaths are most often expressed as a rate, often deaths per 100 million vehicle-miles or per billion vehicle-miles, or, for international comparisons, as deaths per billion vehicle-km.

Historical Trends[edit]

Safety overall has steadily improved in the United States for many decades. Between 1920 and 2000, the rate of fatal automobile accidents per vehicle-mile decreased by a factor of about 17.[5][6] Except for a pause during the youth bulge of the 1960s (a time when many young, inexperienced drivers were on the road), progress in reducing fatal accidents has been steady. Safety for other types of U.S. passenger transportation has also improved substantially, but long-term statistical data are not as readily available.[citation needed] While the fatality rate roughly leveled off around 2000–2005 at around 1.5 fatalities per 100 million miles traveled, it has resumed a downward trend and reached 1.27 in 2008.[5] The National Safety Council (whose data methodology differs slightly from the NHTSA) reports a rate (including deaths of pedestrians and cyclists killed in motor vehicle accidents) of 1.25 deaths per 100 million vehicle miles (or 12.5 deaths per billion vehicle miles) traveled in 2016.[7]

United States compared to other nations[edit]

The fatality rate in the United States is high relative to most other high income nations. The 2013 U.S. rate of 7.1 road fatalities per 1 billion vehicle-km is about double the 2013 rate in Sweden, which was 3.5 road fatalities per 1 billion vehicle-km. (See: List of countries by traffic-related death rate.) To some extent this is due to geography and driver training, but more rigorous impaired driving enforcement and severe penalties in Sweden for driving under the influence may also explain the difference. While it might be argued that highways and vehicles in Sweden are different from those in the United States, the U.S. fatality rate is also about double the rate in the Canadian province of Ontario, which experienced 3.6 road fatalities per 1 billion vehicle-km according to preliminary 2014 data.[8] Ontario, which is a vast province of more than 1 million square kilometers, has a similar mix of highway types including congested urban and rural highways. Ontario also has a similar mix of large transport trucks essentially identical to U.S. transport trucks, full-sized pickup trucks, SUVs and passenger cars, although there may be more small cars driven in Ontario compared to the United States. This suggests that differences in fatality rates are due to non-physical factors such as driver behavior.

Comparing motorways (controlled-access, divided highways) in Europe and the United States, according to 2012 data, Denmark had the safest motorways with a rate of 0.72 road fatalities per 1 billion vehicle-km, while the United States had 3.38 road fatalities per 1 billion vehicle-km on its Interstate-type highways, often called freeways.[9] In Germany, where significant sections to the Autobahn network do not have mandatory speed limits, the death rate on such highways was 1.74 road fatalities per 1 billion vehicle-km, about half the U.S. rate for Interstate-type highways. (For chart, see: Safety: international comparison)

Fatality rates by state[edit]

The death rate per 100 million miles traveled in 2015 ranged from 0.52 in Massachusetts to 1.89 in South Carolina.[10] (The Massachusetts rate translates to about 3.25 fatalities per 1 billion vehicle-km. The South Carolina rate translates to about 11.8 fatalities per 1 billion vehicle-km.) In South Carolina, North Dakota and Texas, more than 40% of road fatalities were attributed to Driving Under the Influence.[11] A plot of Vehicles Miles Traveled Per Capita vs Fatalities per 100,000 Population shows Montana, South Carolina and West Virginia as outliers with higher than expected fatalities.[12]

Enforcement and compliance with seat belt laws varies by state. (Massachusetts, which had the lowest death rate per 100 million miles traveled in 2015, was among the states with the lowest use of seat belts.) Some states require motorcycle helmets while others do not. Speed limits, traffic density, topography, climate and many other factors affect the divergent accident rates by state. Speed limits in Texas, Utah, and Rhode Island are prima facie rather than absolute. This allows motorists in those states to defend against a speeding charge if it can be proven that the speed was in fact reasonable and prudent. In good driving conditions, many drivers in prima facie states presume (usually correctly) that police will allow some tolerance in enforcement. Even in states with absolute speed limits, enforcement and penalties vary from one state to another. For these and other reasons, state to state comparisons are difficult. There are many studies examining increases in Interstate speed limits from 55 mph to 65, 70 and 75 mph. Some found that fatality rates increased significantly on Interstate highways where speed limits were raised.[13] One study that examined the change from 55 to 65 mph found higher Interstate speed limits improved overall highway safety by drawing traffic from less safe secondary highways to safer Interstate highways.[14] Since the changes to 80 mph speed limits in some states (and 85 mph on one section of a toll highway in Texas) are relatively recent, robust analysis is not yet available. Anecdotal evidence suggests actual vehicle speeds did not increase as much as speed limits did. Also, police may be enforcing the new higher limits more strictly than they enforced the prior limits. In some states, police have reallocated resources to focus more on impaired and distracted driving.[15] The higher speed limits are predominantly in rural states, which tend to be Republican states. To many Republican voters, speed limits (and seat belt laws) are seen as intrusions on personal liberty. According to transportation historian Owen Gutfreund, state governments may raise speed limits because raising the speed limit “sounds like such an easy regulatory win.” It’s a simple way to “get government out of your face.”[16]

Pedestrians and cyclists[edit]

As cars have become safer for occupants (due to airbags, structural crashworthiness and other improvements) the percent of pedestrian fatalities as a percent of total motor vehicle fatalities steadily increased from 11% in 2004[17] to 15% in 2014 according to NHTSA data.[18] Bicyclists accounted for 2 percent of all traffic deaths in 2014.[19]

Rates per driver's license[edit]

One can also calculate auto fatalities per driver's license. From 1990 to 2009, this number has also been improving: from 1 death per 3,745 driver's licenses in 1990 to 1 per 6,200 driver's licenses in 2009.[20] Crowded, traffic-choked Northeastern cities including, Washington, D.C., Baltimore, Boston, Providence, Philadelphia, Newark, Hartford, New Haven, Springfield and Worcester, Massachusetts were most likely to have car accidents.[21] The National Highway Traffic Safety Administration through its Fatality Analysis Reporting System stated that auto fatalities continue to be the leading cause of death for young adults.[22]

Driving versus flying[edit]

The number of deaths per passenger-mile on commercial airlines in the United States between 2000 and 2010 was about 0.2 deaths per 10 billion passenger-miles, [23] [24] while for driving, the rate was 1.5 per 100 million vehicle-miles for 2000, which is 150 deaths per 10 billion miles for comparison with the air travel rate. [5] [25] [26][27]

The greatest risk in flying is in takeoff and landing, meaning that longer aircraft trips are safer per mile. Commuter planes used on shorter flights have higher risk than larger jet aircraft. Driving on U.S. Interstate highways, which are almost always controlled-access divided highways, is safer than driving on other most other roads and highways.

Unlike the large U.S. air carriers and commuter airlines, which on average has less than 20 fatalities annually, each year general aviation fatalities number in the hundreds. Most general aviation accidents involved single-engine, piston-powered airplanes used in recreational aviation. [28]

Risk factors[edit]

Rural non-Interstate highways are particularly risky. Most are two-lane non-divided highways built to lower standards than Interstate highways. Drivers are often drunk and not wearing seat belts. Speeding is common. Deer, elk and moose crossing the highway add to the risk compared to urban highways. In the event of an accident in a remote area, injured victims may not receive emergency medical care in time to save their lives.[29]

Many accidents when driving personal vehicles are caused by distracted driving. According to the American Automobile Association (AAA), distraction plays a factor in 60% of moderate to serious teen car crashes. Specifically, passenger and cell phone interaction accounted for 27% of crashes, the leading cause. Drivers looking away from the target (roadway) also accounted for 19%.[30]

Non-use of seat belts is a significant risk factor. According to Col. Tom Butler, chief of the Montana Highway Patrol, preliminary 2015 data indicated that 178 of the 224 vehicle occupant fatalities were of individuals not wearing seat belts.[31] The fine in Montana for not wearing a seat belt in 2015 was $20. Although speed limits increased from 75 mph to 80 mph on rural interstates that year, the biggest statewide increase in both crashes and deaths occurred on secondary roads. Forty-three people died on Montana two-lane roads outside of towns that are neither U.S. or state highways.[32]

Average trip duration may be greater in rural states, which may mean driver fatigue is a more salient risk factor in rural states than in more densely populated states. Most data on the number of hours driven in a day and accident rates is for commercial drivers who are required to keep driving logs. (See next section.)

Commercial drivers and air pilots[edit]

A graph outlining the relationship between number of hours driven and the percent of commercial truck crashes related to driver fatigue.
Source: Federal Motor Carrier Safety Administration[33]

Driver fatigue is a concern, particularly for commercial drivers. Hours of service regulations are issued by the Federal Motor Carrier Safety Administration (FMCSA) and govern the working hours of anyone operating a commercial motor vehicle (CMV) in the United States. The relationship between number of hours driven and the percent of commercial truck crashes related to driver fatigue is an exponential relationship. (See graph.)

Although the accident rate per 100 million miles for professional truckers is low, the high number of miles driven by a truck driver makes truck driving a risky occupation. Trucking transportation occupations accounted for one quarter of all work-related fatalities in 2015, more than any other U.S. job, according to the U.S. Labor Department’s Bureau of Labor Statistics' annual workplace fatality report.[34] The fatal injury rate in 2015 was 14.7 per 100,000 full-time equivalent workers in transportation and material moving occupations (which includes both truckers and air transportation workers.)[35] This was a significantly lower rate than for workers in farming, fishing, and forestry occupations, but high compared to most other occupation categories. The report did not break out the fatal injury rate per 100,000 full-time equivalent workers among aircraft pilots and flight engineers but did note that they had a high fatal injury rate compared to all workers. There were 57 fatalities among aircraft pilots and flight engineers in 2015.[36]

Rail and bus[edit]

Rail and bus (motorcoach) accidents also account for fatalities, although public transportation is far less dangerous than driving a personal vehicle.[citation needed]

See also[edit]


  1. ^ "FastStats Homepage - Injuries". Centers for Disease Control and Prevention - National Center for Health Statistics. Retrieved 14 March 2017. 
  2. ^ "2015 Motor Vehicle Crashes: Overview". National Highway Traffic Safety Administration. Retrieved 14 March 2017. 
  3. ^ "2015 Motor Vehicle Crashes: Overview". National Highway Traffic Safety Administration. p. 10. Retrieved 14 March 2017. 
  4. ^ Beene, Ryan (15 February 2017). "Deaths on U.S. Roads Reach Highest Since 2007 Amid More Driving". Bloomberg. Retrieved 14 March 2017. 
  5. ^ a b c "Fatality Analysis Reporting System". U.S. National Highway Traffic Safety Administration. 
  6. ^ "Making Sense of Highway Data". U.S. National Motorists Association. Retrieved 22 December 2016. 
  7. ^ Gorzelany, Jim (16 February 2017). "Death Race 2017: Where To Find The Most Dangerous Roads In America". Forbes. Retrieved 13 March 2017. 
  8. ^ "Canadian Motor Vehicle Traffic Collision Statistics" (PDF). Transport Canada (Government of Canada). Retrieved 14 March 2017. 
  9. ^ "International Traffic and Accident Data: Selected Risk Values for the Year 2012" (PDF). Bundesanstalt für Straßenwesen (Federal Highway Research Institute). Bundesanstalt für Straßenwesen. December 2012. Retrieved 2015-11-08. 
  10. ^ "General statistics: Crashes took 35,092 lives in the U.S. in 2015". Insurance Institute for Highway Safety, Highway Loss Data Institute. Retrieved 13 March 2017. 
  11. ^ "Compare Traffic Deaths by State". Find the Data. Retrieved 13 March 2017. 
  12. ^ Kolko, Jed. "Plot of Vehicles Miles Traveled Per Capita vs Fatalities per 100,000 Population". Retrieved 13 March 2017. (States above the regression line have higher deaths per vehicle mile) 
  13. ^ Frisman, Paul (January 18, 2013). "Speed limit increases and accident rates". National Cooperative Highway Research Program. The NCHRP study found that higher speed limits were associated with an increased likelihood of deaths and incapacitating injuries. It found that increasing a speed limit from 55 to 65 mph on an "average" section of high speed road resulted in about a 3% increase in the total number of crashes and a 24% increase in the likelihood that a vehicle occupant would be fatally injured. This increased crash rate would yield a 28% increase in the number of fatalities following the speed limit increase. The study also found a similar, but lesser, impact when speed limits were raised from 65 to 75 mph. In those cases, the total number of crashes increased by 0.64%, increasing the probability of a fatality by 12%, with an overall increase of 13% in total fatalities. Although the analysis did not explain why a smaller increase occurred at the higher speeds, the study suggested that people may drive more cautiously when driving faster, or that roads deemed appropriate for a 75 mph limit are safer. 
  14. ^ Lave, Charles (1995). "Higher Speed Limits May Save Lives". The University of California Transportation Center. the new 65 mph speed limit freed highway patrols to shift resources from speed enforcement on the Interstates to other safety activities and to other highways. It also reallocated traffic by making the safer Interstate Highways more attractive. 
  15. ^ Marshall, Aarian (May 4, 2016). "Raising Speed Limits Is Irresponsible, But States Keep Doing It". Wired. 
  16. ^ Marshall, Aarian (May 4, 2016). "Raising Speed Limits Is Irresponsible, But States Keep Doing It". Wired. 
  17. ^ "Traffic Safety Facts - Pedestrians (2013 Data)". NHTSA. Retrieved 13 March 2017. 
  18. ^ "Traffic Safety Facts - Pedestrians (2014 Data)". NHTSA. Retrieved 13 March 2017. 
  19. ^ "Bicyclists". NHTSA. Retrieved 13 March 2017. 
  20. ^ "Table 1105. Fatal Motor Vehicle Accidents—National Summary: 1990 to 2009". U.S. Census Bureau. Retrieved 22 December 2016. 
  21. ^ Doyle, Rice (11 November 2014). "Northeastern Cities Have the Most Car Accidents". USA Today. Retrieved 12 May 2015. 
  22. ^ "NHTSA Data Confirms Traffic Fatalities Increased In 2012". U.S. Department of Transportation. National Highway Traffic Safety Administration. 14 November 2013. Retrieved 22 December 2016. 
  23. ^ "Fatalities Bureau of Transportation Statistics". 
  24. ^ "Passenger miles Bureau of Transportation Statistics". 
  25. ^ "Aviation". 
  26. ^ Arnold Barnett (1991). "It's Safer to Fly". Risk Analysis. 11 (1): 13–14. doi:10.1111/j.1539-6924.1991.tb00558.x. 
  27. ^ Peter B. Ladkin (1997). "To Drive or To Fly". University of Bielefeld. 
  28. ^ "Bureau of Transportation Statistics annual report". 
  29. ^ Berkes, Howard (29 November 2009). "The Deadliest Roads Are Rural". National Public Radio. Retrieved 13 March 2017. 
  30. ^ Manookian, Brian. "Statistical Risks Of Driving And Related Acts". Cummings Manookian. Retrieved 22 December 2016. 
  31. ^ Briggeman, Kim (January 4, 2016). "Montana highway death toll up sharply in 2015". Missoulian. 
  32. ^ Briggeman, Kim (January 4, 2016). "Montana highway death toll up sharply in 2015". Missoulian. 
  33. ^ "Regulatory Impact and Small Business Analysis for Hours of Service Options". Federal Motor Carrier Safety Administration. Retrieved 2008-02-22. 
  34. ^ Rafter, Michelle. "Driving a Truck is Among Deadliest Jobs in the U.S.". Retrieved 13 March 2017. 
  35. ^ "Census of Fatal Occupational Injuries Summary, 2015, Table 3". U.S. Department of Labor, Bureau of Labor Statistics. Retrieved 13 March 2017. 
  36. ^ "Census of Fatal Occupational Injuries Summary, 2015". U.S. Department of Labor, Bureau of Labor Statistics. Retrieved 13 March 2017.