Statistics & Their Role In Car Accident Research

In recent decades, American society has become obsessed with statistics. We worry over numbers, spreadsheets, and this often mystifying concept of “big data.” And while statistics were once the province solely of highly-specialized analysts, numbers are now a national preoccupation.

What Can Statistics Tell Us About Car Accidents?

According to the American Statistical Association, “statistics is the science of learning from data, and of measuring, controlling, and communicating uncertainty.” But what does that mean?

What Is / Are Statistics?

In statistics, “uncertainty” has a specialized definition. For obvious reasons, no one person can know everything. We can’t know about every car accident that occurs in Philadelphia because some go unreported, papers get lost, etc. So statistical researchers have to limit what they’re looking at, make the boundaries tighter.

Instead of trying to make our object of study “every car accident in Philadelphia,” we can talk about “every car accident in Philadelphia that was reported to the police.” But in some cases, for whatever reason, the police might not file a formal report, even if they are notified of an accident. So we could limit our object of study further to “every car accident in Philadelphia that was reported to the police and the police actually filed a report.” Through all these steps, we’re attempting to limit the possibility of error by refining our terms.

The Real Work Of Statisticians

But we haven’t even reached the meaning of “uncertainty” yet! Uncertainty comes in when we make the next move, and try to say things about people or places in general based on what we know about our limited, refined objects of study.

Say that we find that, out of “every car accident in Philadelphia that was reported to the police and the police actually filed a report,” 30% are rear end accidents and 5% result in fatal injuries.

The question becomes: is it legitimate to extrapolate from this data, to assume that 30% of all accidents are actually rearenders, and that 5% of all car accidents actually result in death? This is the step that is uncertain, and it’s the real work of statistics, a work in progress.

Why Do Statistics?

Measuring and controlling uncertainty involves identifying risk, and protecting against it wherever possible. In regard to car accidents, large statistical research projects tell us that 28 percent of all fatal traffic collisions occur between 6 p.m. and midnight. You probably could have guessed that – people get tired at night, and their driving abilities suffer. But there are numerous questions that don’t have simple, logical answers, and many seemingly simple ones that defy our initial attempts at reasoning.

Answers That Defy Reason

Before consulting any actual data, you might expect that more accidents occur in urban areas, thickly settled and crammed with cars, than on lonesome, empty rural roads. But the numbers don’t bear that out. In fact, a recent study by the National Highway Traffic Safety Administration (NHTSA) found that 4,000 more deadly traffic collisions occur on rural byways than city streets every year.

Making Change In The Real World

From this research alone, we’ve identified a domain of greater risk: more accidents happen in rural areas than urban. And after more analysis, we might be able to propose reasons why. Maybe drivers are more likely to speed when they are further from city centers, maybe not. But an answer lies somewhere within the numbers and accident reports.

With these answers in hand, vehicle manufacturers can begin to make safer cars and politicians can create more responsible public policy. Once we’ve identified where risk is, and why it is, we can begin to tackle reducing it.

Why Do Car Accident Statistics?

There are few domains more appropriate for statistical research than car accidents. For one, we have a relatively large, and accurate, sample population from which to draw conclusions. Police in every state are legally obligated to write accident reports after each crash. And slowly, through long hours of analysis and theorization, we arrive at tentative conclusions about different populations, and hopefully, people in general.

In statistics, we look for answers. We search for the link between abstract sample populations and our own lives. But because of statistical uncertainty, every quoted number should be taken with a grain of salt. Get out your shaker, because we’re going to dive into some numbers.

Car Accident Statistics By Type

We’ve already presented general car accident statistics, both for the nation and Pennsylvania, here. Now, we’re going to break it down further, and discuss statistics by car accident type.

Texting While Driving

  • In 2011, at least 23% of auto collisions involved cell phones. That translates to 1.3 million crashes.
  • 13% of drivers age 18 – 20 involved in accidents admitted to texting or talking on their mobile devices at the time
  • 27% of adults have admitted to sending or receiving text messages while driving

We tackled the question of whether texting while driving is a “teen” problem in an earlier blog post. You can find it here. All statistics drawn from Texting & Driving Safety.

Drunk Driving

  • On average, two in three people will be involved in a drunk driving accident within their lifetime.
  • Someone dies in a drunk driving accident every 51 minutes.
  • The average drunk driver has driven drunk 80 times before their first arrest.
  • Drunk driving is most common among 21 to 25 years old. 23.4% have driven drunk.

All statistics quoted from Mothers Against Drunk Driving.

High Speed Collision

  • Low speed drivers are more likely to be involved in accidents than relatively high speed drivers.
  • Excessive speed is a contributing factor to one out of every three fatal car accidents.

Statistics drawn from Smart Motorist and this 2005 study performed on behalf of the Insurance Institute for Highway Safety.

Head On Collision

  • 75% of head-on collisions occur on rural roads.
  • According to a 2005 study, only 2% of all crashes were head-on collisions, but they accounted for over 10% of all fatal accidents.

Statistics can be found on the Strategic Highway Safety Plan website.

Side Impact Collision

  • According to the Insurance Institute for Highway Safety, “between 1981 and 2001, frontal impact fatalities for all occupants dropped from 61 percent to 43 percent due to significant improvements in frontal crash protection […] During the same 20 year span, the percentage of side impact fatalities rose from 31 percent to 51 percent due mainly to the increase of travel speeds and the amount of SUVs on the road.”
  • “Side impact collisions are among the deadliest type of collision for children, accounting for 1 in 3 child crash fatalities.”

Statistics quoted from Safety 1st.

Asleep At The Wheel / Drowsy Driving

  • The NHTSA estimates that “100,000 police-reported crashes are the direct result of driver fatigue each year.”
  • Adults between 18 and 29 are more likely to drive drowsy than any other age groups. Men are more likely than women.

More statistics can be found on

Rollover Accidents

  • “Rollover crashes account for 33% of all passenger vehicle fatalities.”
  • “More than 10,000 people a year are killed in rollover crashes.”

All statistics quoted from the NHTSA’s

Rear End Accidents

  • According to the NHTSA, 28% of all collisions are rear end accidents.
  • Rear end collisions accounted for “11.8% of multivehicle fatal crashes” in 1999.

Find more statistics at the National Transportation Safety Board.

Wrongful Death

  • In 2012, there were 30,800 fatal crashes in America.
  • Every day, around 80 people die in traffic accidents.

Find detailed fatality statistics for the years 1994 through 2012 on the NHTSA website.