Jay Dickey, a Republican and life member of the NRA, represented Arkansas in the House from 1993 to 2000. Mark Rosenberg, president and chief executive of the Task Force for Global Health, was director of the National Center for Injury Prevention and Control at the U.S. Centers for Disease Control and Prevention from 1994 to 1999.

A few years ago, one of us came across a young woman who had just been hit by a car. She was the mother of two young children and one of Atlanta’s star runners. I found her unconscious and bleeding profusely from a severe head injury. She died in my arms while I tried to resuscitate her.

Her death was tragic, but it wasn’t “senseless.” In scientific terms, it was explicable. The runner, who had competed in 15 marathons and broken many records, wore no lights or reflective vest in the early-morning darkness; she crossed the street within crosswalk lines that had faded to near-invisibility; there were no speed bumps on this wide, flat street to slow cars down.

Scientists don’t view traffic injuries as “senseless” or “accidental” but as events susceptible to understanding and prevention. Urban planners, elected officials and highway engineers approach such injuries by asking four questions: What is the problem? What are the causes? Have effective interventions been discovered? Can we install these interventions in our community?

The federal government has invested billions to understand the causes of motor vehicle fatalities and, with that knowledge, has markedly reduced traffic deaths in the United States. Since the mid-1970s, research has inspired such interventions as child restraints, seat belts, frontal air bags, a minimum drinking age and motorcycle helmets. The National Highway Traffic Safety Administration estimates that 366,000 lives were saved through such efforts from 1975 to 2009.

Through the same scientific, evidence-based approach, our country has made progress understanding and preventing violence. Once upon a time, law-abiding citizens believed that violence generated by evil always had existed and always would exist. By the mid-20th century, that sense of fatalism was yielding to discoveries by social scientists, physicians and epidemiologists. Now a body of knowledge exists that makes it clear that an event such as the mass shooting in Aurora, Colo., was not a “senseless” occurrence as random as a hurricane or earthquake but, rather, has underlying causes that can be understood and used to prevent similar mass shootings.

We also recognize different types of violence, including child abuse and neglect, sexual assault, elder abuse, suicide and economically and politically motivated violence. Like motor vehicle injuries, violence exists in a cause-and-effect world; things happen for predictable reasons. By studying the causes of a tragic — but not senseless — event, we can help prevent another.

Recently, some have observed that no policies can reduce firearm fatalities, but that’s not quite true. Research-based observations are available. Childproof locks, safe-storage devices and waiting periods save lives.

But it’s vital to understand why we know more and spend so much more on preventing traffic fatalities than on preventing gun violence, even though firearm deaths (31,347 in 2009, the most recent year for which statistics are available) approximate the number of motor vehicle deaths (32,885 in 2010).

From 1986 to 1996, the U.S. Centers for Disease Control and Prevention (CDC) sponsored high-quality, peer-reviewed research into the underlying causes of gun violence. People who kept guns in their homes did not — despite their hopes — gain protection, according to research published in the New England Journal of Medicine. Instead, residents in homes with a gun faced a 2.7-fold greater risk of homicide and a 4.8-fold greater risk of suicide. The National Rifle Association moved to suppress the dissemination of these results and to block funding of future government research into the causes of firearm injuries.

One of us served as the NRA’s point person in Congress and submitted an amendment to an appropriations bill that removed $2.6 million from the CDC’s budget, the amount the agency’s injury center had spent on firearms-related research the previous year. This amendment, together with a stipulation that “None of the funds made available for injury prevention and control at the Centers for Disease Control and Prevention may be used to advocate or promote gun control,” sent a chilling message.

Since the legislation passed in 1996, the United States has spent about $240 million a year on traffic safety research, but there has been almost no publicly funded research on firearm injuries.

As a consequence, U.S. scientists cannot answer the most basic question: What works to prevent firearm injuries? We don’t know whether having more citizens carry guns would decrease or increase firearm deaths; or whether firearm registration and licensing would make inner-city residents safer or expose them to greater harm. We don’t know whether a ban on assault weapons or large-capacity magazines, or limiting access to ammunition, would have saved lives in Aurora or would make it riskier for people to go to a movie. And we don’t know how to effectively restrict access to firearms by those with serious mental illness.

What we do know is that firearm injuries will continue to claim far too many lives at home, at school, at work and at the movies until we start asking and answering the hard questions. “Such violence, such evil is senseless,” President Obama said last week. What is truly senseless is to decry these deaths as senseless when the tools exist to understand causes and to prevent these deadly effects.

We were on opposite sides of the heated battle 16 years ago, but we are in strong agreement now that scientific research should be conducted into preventing firearm injuries and that ways to prevent firearm deaths can be found without encroaching on the rights of legitimate gun owners. The same evidence-based approach that is saving millions of lives from motor-vehicle crashes, as well as from smoking, cancer and HIV/AIDS, can help reduce the toll of deaths and injuries from gun violence.

Most politicians fear talking about guns almost as much as they would being confronted by one, but these fears are senseless. We must learn what we can do to save lives. It is like the answer to the question “When is the best time to plant a tree?” The best time to start was 20 years ago; the second-best time is now.