It had been a maxim in the automotive safety community that the rear seat was safer than the front, says the study’s lead author, Dennis Durbin, M.D., director of the Office of Clinical and Translational Research at The Children's Hospital of Philadelphia.

“I always used to say that, if I could figure out a way to drive from the back seat I would,” Durbin says.

But in the last five years, some studies have shown that the relative safety advantage of the back seat has begun to shrink, particularly in newer vehicles and particularly for adults.

“We have reduced the likelihood of dying in a crash in the front seat; we know there are things we can do in the rear seat,” Jermakian says.

Those strategies include adding features that help reduce chest injuries such as seat-belt pretensioners and load limiters, which front seat belts have had for years, but rear belts, with rare exceptions, have not. Belt pretensioners remove excess slack in a crash. Load limiters allow some of the seat belt to strategically spool out—if it didn’t, the overly tensioned seat belt could break your ribs or other bones by not giving the body sufficient slack to absorb the shock.

Among the other suggestions: Adding rear-seat reminder chimes, to increase seatbelt use. A recent NHTSA study shows that front-seat seatbelt use is 87 percent, a figure that drops sharply to 78 percent in rear seats for passengers 8 and older.

The National Highway Traffic Safety Administration has contracted with the University of Michigan and automotive supplier ZF TRW to study rear-seat restraint systems such as rear airbags that deploy from the roof or from the back of a front seat. Currently, rear-seat occupants only have airbags that provide protection in side impacts.

What’s available right now?

Volvo, has added seat-belt pretensioners and load limiters to its rear seatbelts in all its vehicles. And, if a child is seated in a Volvo’s integrated booster seat, the load limiter adjusts to limit the force of the impact even more.

For mass-market shoppers, Ford has developed rear-seat safety technology with its Rear Inflatable Belt, introduced in the 2011 Explorer.

A tubular airbag concealed in the shoulder belt inflates in a crash to reduce head, neck and chest injuries. It’s a $195 option on the Ford Explorer, Edge, F-150, Flex and Fusion and the Lincoln MKZ and MKT.

Mercedes-Benz has similar technology. Its rear-seat Beltbag is available on the S-Class sedans as part of an optional rear seat package and standard on the S600 and S65 AMG sedan.

In Consumer Reports’ evaluations, however, those inflatable belts may make it harder to install child restraints and for children to buckle themselves up. Overall, we think inflatable belts are a good step forward, but there are still some kinks to work out.

Toyota is conducting research related to two vulnerable groups mentioned in the study—children between 9 and 12, and adults 55 and older. Partnering with Wayne State University, Toyota is developing computerized “virtual models” of a 10-year-old and a 70-year-old to help better understand crash injuries using computer simulation.

NHTSA, the federal safety agency, also has proposed changes to its 5-Star Safety Rating System for new vehicles such as adding a “Silver” rating to provide crash safety information for older consumers, and a “Family Star” rating, to rate vehicles on how well they protect children in the rear.

Part of the challenge is the wider age range of people who sit in the back—from infants to 90-year-olds. It will be important that engineering solutions not help one group at the expense of the other.

—Cheryl Jensen