Are SUVs and Big Cars the Safest on the Road? Not Always

We all get unsolicited advice on which car is the safest to buy. Some might say that heavier and bigger cars are the safest cars on the road, while others will tell you to avoid the lighter ones because they lead to a higher risk of fatalities and accidents.

So maybe what this means then is that the lighter, more fuel-efficient car gets forgotten in the mix, and that SUV gets a nod from your entire family because they're huge and heavy.

But are these truths or fallacies? In most cases, they are true -- but you're not entirely seeing the entire picture here, either.

Two Types of Risks

Truth is, there's more to safety than size and weight. And there's certainly more to safety than guaranteeing you'd come home in one piece. Many safety analysts tend to overemphasize the safety risks that drivers of a particular car model will get, when it's also important to consider how their cars will affect the safety of other drivers around them.

Combining these two kinds of risks make evaluating a car's overall danger on the road more comprehensive and accurate. When these two risks are combined, SUVs are actually no safer than subcompact or compact sedans -- or any other car*. What's more, those who drive pickup trucks actually stand a much greater risk compared to SUV drivers. In fact, combining both risks show that SUVs and pickup trucks pose a much greater danger compared to most cars on the road.

Perhaps our concept of the safest cars may not be accurate, after all.

Here is a chart to help you understand the safety risk of drivers and other drivers using different vehicle types on the road:

Factors that affect a car's safety risk

Keep in mind that the chart above is just an overview. Not all cars are the same, just as not all drivers are the same. And there are just as many factors that affect a car's safety risk. They include:

Weight

Just like everything else, vehicles are also affected by the laws of physics. So when two mismatched cars collide with each other, the lighter vehicle takes the heavier impact between the two.

In fact, the odds of a fatal accident between a car and SUV driver are 7.6 times higher for the person driving the car than the SUV. And even if the car has a well-rated front crash feature than the SUV did, the driver is still four and a half times more likely to die than the SUV driver.

In case of side and rear collisions during lane changes, the car driver still has the disadvantage. Small vehicles tend to crumple when a violent impact hits it from these areas. And even the presence of airbags can only do little in the face of quickly bending metal.

Larger vehicles also lessen the amount of collateral damage that happens in a crash. In the Insurance Institute Study (IIHS), only 8% of vehicular deaths involved passengers in the back seat of large cars.

So does this mean that passenger cars like sedans are walking death traps? Certainly not. In fact, they can actually be as safe as SUVs and other larger cars if they improve their design.

Design

Improving a car's design and safety features can actually lessen fatality risk even in light or small cars. A study made by IIHS researchers found out that vehicle changes like added safety technology and improved structural design were the main source of decline in car fatality risks that happened in the U.S. from 1993 to 2006.

One good example of how design can impact a car is seen in small overlap crash tests. In the real world, crashes don't always occur head-on. And in some cases, the impact usually happens at an angle, such as when your car's front corner collides with another car or a tree. These are called small overlap crashes.

These crashes, which are very demanding on airbags and safety belts, can result to more lower extremity injuries compared to direct, full frontal crashes. They are debilitating, since 40 percent of the serious injuries happen on the lower legs and feet. What's more, they're costly to maintain, since drivers who face this type of accident are unable to work for three months or longer.

Vehicle manufacturers often design their cars for moderate to full frontal crashes -- not the smaller ones. So they have adjusted their designs and included better airbags on the front and side, as well as widening front-end structures and strengthening the safety cage of their cars to resist deformation from side impacts.

These design tweaks have made many cars today much safer on the road -- especially smaller cars.

Environment and Road Conditions

The environment also has a say when it comes to safety risks. This is particularly true for those that experience heavy rain. Rain causes poor visibility and slippery roads -- two factors that can lead to collisions or accidents.

However, it's interesting to note that the impact of adverse weather and the seriousness of the injuries appear to be less fatal, falling by 28.9 percent. This can be attributed to drivers who practice more caution and lesser speeds during bad weather.

Weather is not the only factor here. Locations where vehicles are used should also be taken into consideration. For example, pickup trucks have high risk ratings mainly because they are used in rural places that offer poor road conditions and higher speeds (due to lesser traffic).

Driver Behavior, Gender and Age

Driver behavior is hard to measure, since they vary depending on the person. But whatever the case, it's a known fact that there is a direct correlation between aggressive drivers and fast vehicles -- particularly the sportier ones.

Sports cars go hand-in-hand with speed, and there's a huge body of evidence that consistently supports the theory that increasing speed increases a person's chances of crashing, getting injured or killed. For fatalities, there's around 4 percent to 12 percent fatality risk for every one percent increase in speed.

Safety risks can also be affected by age and gender. However, a study made by Wenzel and Ross showed that behavior, age, and gender don't have enough influence in determining a vehicle type's safety risk factor. On the other hand, weight, design, and even the car's price have the highest significance in influencing the degree of safety that a driver and his fellow drivers will experience on the road.

How to Choose the Safest Cars

The information above might not mean anything to someone whose priority is to buy a cheap, low-quality car. If you're that person, then keep in mind that the savings you make when purchasing an inexpensive car can easily be wiped out with the medical costs of just one serious accident.

When driven responsibly, SUVs are still the safest cars when it comes to overall safety. But if you're opting to buy a small car, then it's best to invest in as many safety features that you can get as possible. And make sure that they are all up-to-date. That way, you're almost getting the benefits of an SUV -- without the hefty price tag that comes along with it.

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*   Taken from the research paper: "An Analysis of Traffic Deaths by Vehicle Type and Model," prepared by Tom Wenzel, an energy analyst with Berkeley Lab's Environmental Energy Technologies Division, and Marc Ross, a professor in Michigan's Applied Physics Department.

**  "An Analysis of Traffic Deaths by Vehicle Type and Model," by Wenzel and Ross

*** “The Roles of Vehicle Footprint, Height, and Weight in Crash Outcomes: Application of a Heteroscedastic Ordered Probit Model” By T. Donnachen

     "The Aggressivity of Light Trucks and Vans in Traffic Crashes," Gabler, H.C. and W.T. Hollowell