What You Need to Know About SUVs and Safety

Many American drivers have purchased sport utility vehicles to feel safe. But are they really safe, or do drivers simply believe so because they feel encased in a large, heavy vehicle? Just a few years ago, people were probably far less safe than they thought.

A brief study in the area of SUV safety suggests two things:

• The protection afforded by the vehicles' greater weight is overestimated.
  
  
• The chance of rollover fatality — as a function of the vehicle itself — is also overestimated.

Cars.com can't designate a vehicle as safe or unsafe. What we can do is interpret crash-test and rollover ratings and provide a guide to safety features. For what it's worth, crash tests are increasingly proving indicative of real-world performance. The two third-party agencies that perform the tests are the federal government's National Highway Traffic Safety Administration and the Insurance Institute for Highway Safety, a nonprofit organization funded by the insurance industry.

Cars.com by far favors the IIHS results because they are closer to real-world crashes, as explained in our Guide to Crash Tests and Rollover Ratings. "It has taken [10 years] to accumulate enough real-world crash fatality data to make the comparisons between crash-test ratings and experience in real crashes," said Adrian Lund, the IIHS's chief operating officer. "What we've found is that the tests are very good predictors of fatality risk."

Though weight is a factor in collisions, it isn't the only one. All other things being equal, a heavier vehicle will fare better in a crash with a smaller one. But all other things are never equal. The truck-based vehicles that spawned the SUV revolution had nowhere near the crash protection built into them as did the common unibody car. Body-on-frame trucks were built to be tough, not to absorb crash energy by means of crumple zones. They also had high centers of gravity and were tipsy when compared to other vehicle types.

Ironically, now that SUV safety has come under greater scrutiny and NHTSA has issued rollover ratings, two of the biggest safety issues have started to fade on their own. Automakers have begun to incorporate crumple zones into their truck-based SUVs, which are earning much improved crash-test ratings. Unlike early-generation SUVs, the new and completely redesigned truck-based models of the past few years are being built with wider tracks (the distance between the left and right wheels), lowered bodies and/or other measures to lower their center of gravity. Is it any wonder that the SUV with the worst score in the 2004-model-year rollover ratings (2 stars out of 5) is not a recent model but the two-wheel-drive Ford Explorer Sport Trac — a combination SUV/pickup that's based on the previous-generation truck platform?

Statistics: Should They Scare or Soothe?

SUVs and rollovers just go together, right? To an extent, yes. But if you dig deep into the statistics, you might find that rollover risk can be diminished and the possibility of fatality from a rollover can also be minimized. The most popular statistics from NHTSA are:

• Rollovers constitute 3 percent of passenger-vehicle crashes but account for nearly 33 percent of all deaths.
  
  
• Nearly 85 percent of all rollover-related fatalities are the result of single-vehicle crashes, in which the vehicle rolls over or collides with an obstacle other than another vehicle.

The conclusions one could draw from these stats is that SUVs are so unstable they roll over even if you don't collide with anything, and when it happens, it's so catastrophic that you probably won't survive. But if you look at some other NHTSA stats, the picture looks different:

• The majority of victims in rollover fatalities (72 percent) were not wearing safety belts.
  
  
• You're 75 percent less likely to be killed in a rollover if you're wearing a seat belt.
  
  
• Speeding is implicated in 40 percent of fatal rollover crashes — more than in fatal non-rollover crashes.
  
  
• Nearly half of all fatal rollover crashes involve alcohol.
  
  
• Almost 75 percent of fatal rollovers occur on undivided rural roads where the posted speed limit is 55 mph or higher.
  
  
• More than 90 percent of the vehicles in fatal, single-vehicle rollover crashes were involved in routine driving maneuvers (going straight or negotiating a curve, as opposed to an evasive maneuver) at the time of the crash. This highlights the role of the driver.

Given what we know about modern vehicles and these statistics, it's not unreasonable to conclude that if you buy a new car-based SUV, don't drink, don't speed, wear your seat belt and don't drive like a moron, chances are pretty good you won't roll over, or at least you'll survive if you do. If you seldom drive on rural roads, that's another element in your favor. If you want even more protection, look for some of the features detailed below.

Safety Features for SUVs

General Motors' electronic stability system — StabiliTrak — is standard on the Cadillac Escalade.

Some of the desired safety features for SUVs are the same as those for any vehicle: antilock brakes, three-point (lap-and-shoulder) seat belts and head restraints in all seating positions, multistage frontal airbags and occupant classification in the front passenger seat, which determines the occupant's weight (and thus size) and fires the airbag at one of two or more levels of intensity.

There are three features that are especially useful in SUVs, and one you should avoid, if safety is a concern:

1. Electronic stability systems: Sold under names like ESP, StabiliTrak, DSTC, VSC, VDC — and the list goes on — electronic stability systems can limit acceleration and apply any of the antilock brakes to keep you on course if you start to go out of control. It doesn't prevent a rollover, but it's quite effective at preventing conditions that lead to one.

What to look for: Don't confuse this feature with simple traction control (also sold under acronym names), which only prevents wheelspin upon acceleration. Don't mess around. Be positive that an electronic stability system is what you're getting.

2. Side curtain-type airbags: This type of airbag deploys downward from the ceiling to cover some or all of the side windows upon side impact. One could argue that this type of airbag is less important on taller vehicles because other tall vehicles are likely to strike your SUV's door sills or doors, which absorb energy. (A car, on the other hand, would have only windows and narrow pillars to protect its occupants from a collision with a truck.) But side-curtain airbags can serve another purpose in some models in the event of a rollover: They protect occupants and help keep them inside the vehicle. They stay inflated long enough for several rolls.

The side curtain-type airbags in the Volvo XC90 provide protection for outboard occupants in all three rows of seats.

What to look for: Just having side curtain-type airbags isn't enough. Make sure they're designed to deploy in a rollover. Also favor systems that cover all seat rows. Not all three-row vehicles have protection for the third row.

3. Rollover prevention: Something of a holy grail among SUV safety features, a rollover prevention or avoidance system actually senses an impending rollover and triggers the electronic stability system to forestall it. (Stability systems alone can only diminish the chance of tipping up on two wheels to begin with.) The Volvo XC90 was the first vehicle to offer this feature, which the automaker calls Roll Stability Control. Volvo is a division of Ford Motor Co., and the RSC system has begun to spread to other Ford vehicles, including the Lincoln Navigator. As of this writing, no other manufacturer offers the feature, but it's probably only a matter of time.

What to look for: Check our model reports to find which Ford, Lincoln and Mercury products offer RSC.

4. Wheel and tire "upgrades": This is the feature you should avoid if you care about safety and rollover prevention. This will be unpopular with style-conscious buyers, but it has to be said: An increasing number of vehicle owners are customizing their vehicles (wheels and tires being the most common upgrade) in complete ignorance of its effect on safety. To put it plainly, vehicles are designed to work as a system. Change any part and you change multiple characteristics. Wheel and tire combinations that are larger, heavier and/or have greater traction are likely to diminish an SUV's safety. Larger diameters foil antilock brakes and stability systems and can compromise braking. Heavier weight affects the suspension's ability to keep the tire on the road and again affects braking. Tires with greater grip may increase the chance of rollover. If that doesn't convince you, bear in mind that the manufacturer has little or no responsibility for your safety if you've modified the vehicle mechanically. In short, your next of kin would have a tough time in court.

What to look for: If you must customize your vehicle, your best bet is not to go to extremes. Keep the outside diameter of the tire the same, don't increase the wheel diameter too much and think twice about putting significantly different tires on your ride. Believe it or not, the people who built your vehicle — as a unit — really know what they're doing.

Protecting Those Outside Your Vehicle

Rearview cameras, like the one available in the Lexus RX 330, allow drivers to see things they otherwise wouldn't when backing up.

While SUVs are getting better at protecting their occupants, less has been done to protect occupants of smaller vehicles with which they might collide. Improving crash compatibility, as it's called, will require industrywide steps both in the larger and the smaller vehicles. Honda has recently proposed such changes for its own vehicles in the form of a frontal frame structure for cars, designed to contact the bumpers of larger vehicles and engage their crumple zones. Current steps are limited to similar frame extensions on taller vehicles that prevent them from overriding a car's crumple zones.

There are also features that can help protect pedestrians behind vehicles — a significant problem in SUVs that sit high and have large blind spots. One is sonar-based "park assist" that sounds beeps of increasing frequency as the rear bumper nears an obstacle or person. A newer feature, the rearview camera, shows a wide perspective behind the vehicle on a dashboard LCD screen when the vehicle's transmission is in Reverse. Unfortunately, this feature only comes along with expensive optional navigation systems in vehicles such as the Honda Pilot and Lexus RX 330.

Young Drivers and SUVs

Speaking generally, SUVs aren't the best choice for a young or inexperienced driver. Rollovers still loom, and most are single-vehicle accidents. Combine that with the fact that single-vehicle accidents are most common among young drivers, and you can see the danger. The lesson not enough drivers learn is that trucks don't handle or stop like cars. They're generally not as nimble, and they don't stop as short. A young driver who takes a freeway offramp at 50 mph in a sports car might continue unscathed. One who does the same in a family sedan might slide off into the weeds or something less forgiving. One who tries it in an SUV is likely to roll over. Simply put, SUVs are best for drivers who have more self-control than teens, as a rule, do.