Car Size Once upon a time, before NHTSA, air bags, three-point seat belts and all the rest, if you wanted the safest car you went out and bought the biggest car you could find and depended on its mass to protect you. Well, the laws of physics haven’t changed. Modern technology may have made small cars safer, but if you’re going to be involved in a crash your survival odds remain higher in a large car. In one study by the Insurance Institute for Highway Safety (IIHS), insurance-company injury claims showed that among the 17 cars with the highest number of claims, 15 of the cars were small. Two were midsize, and not one was large. Conversely, among the nine cars with the lowest number of injury claims, seven were large cars, two were midsize and not one was small. NHTSA maintains historical research that clearly shows that the occupants of passenger cars are significantly more at risk when involved in a two-car accident with a heavier and higher-riding SUV or truck. Vehicle design with energy-absorbing front and rear bumpers, as well as side-impact air bags, can help mitigate this risk.

Structural Crashworthiness Large car or small, there are differences in injury rates between cars in the same size range. Automakers build two important structures into a car to protect the occupants. The first is a collapsible energy-absorbing structure designed to crush in a controlled manner, absorbing the energy of the crash and increasing the time it takes for the car to come to a stop. The second structure is a reinforced, protective cabin that surrounds the car’s occupants and protects them from injury by keeping the exterior impact from reaching them. Each year NHTSA crash-tests popular models into a fixed barrier at 35 mph. This mimics results from a head-on collision between two vehicles of the same size at that speed. (For that reason, you can compare vehicles only within the same weight class for frontal crash-test results.) The agency also tests for side collisions by sending a 3,015-pound barrier moving at 38.5 mph into the side of a standing vehicle. These tests measure a crash’s impact on the driver and passenger dummies’ heads, chests and thighbones with all of the car’s standard safety equipment in place or deployed. The results, even among different models in the same size class, vary greatly. You can get information on NHTSA’s crash tests at nhtsa.dot.gov. The IIHS also crash-tests cars by sending them into a barrier at 40 mph. It publishes periodic reports, assembled from claims data collected from the institute’s sponsoring insurance companies, that show injury frequencies for popular models. For more information, read the institute’s online brochure “Shopping for a Safer Car,” located under Publications at highwaysafety.org.

For 2011, NHTSA has implemented more stringent testing standards. Because of this, scores for the model years 1990-2010 are not comparable to 2011 vehicle crash ratings. Other changes to the testing procedures for the 2011 model year include the availability of an Overall Crash Rating, a side pole crash test, and the usage of advanced crash-test dummies.

Side Impact Protection All cars are required to meet federal requirements for side impact protection, leading manufacturers to employ a combination of side impact door beams and stronger vehicle structures to reduce potential intrusions. Due to the limited space to absorb an impact - especially compared to a frontal collision - there are significant challenges to protect passengers. Side air bags have become more readily available and affordable, allowing protection found only on luxury cars a decade ago to be available in many new vehicles for as little as a few hundred dollars (with many vehicles having at least front side impact air bags as standard). While not perfect, these supplemental restraints can provide valuable protection. Because the most severe injuries from side impacts involve head trauma, there is greater appeal of curtain or tube systems that specifically protect the head. Both NHTSA and IIHS conduct side impact tests, providing key information for evaluating a vehicle’s safety. However, do remember that most accidents that cause air bag deployment are frontal.

Head Restraints These are popularly known as “headrests,” a terrible misnomer. Their purpose is not to give your head a place to rest but to prevent it from snapping back sharply in a rear-end collision. Though all cars must have front-seat head restraints, not all head restraints are alike. There are two basic kinds, adjustable and fixed. Adjustable head restraints are fine - if they’re adjusted high enough (about ear level) and far enough forward to hit the occupant’s head, not his or her neck. The problem is that few people take the time to adjust their head restraints. The fixed type are always high enough and are probably the best kind for most people. Look too for head restraints in the rear seats. In mid-2004, Saab and Volvo started offering a “whiplash protection system” that allows the seat back to automatically shift rearward during a rear end collision, thus absorbing some of the force and protecting the occupants from whiplash. The most sophisticated systems now include active head restraints that instantly move higher and forward during a rear impact in an effort to further reduce neck injury.

Proper Ergonomics A car’s sound system may reproduce music that’s the next best thing to a live performance, but if the system’s controls are so tiny that you need bifocals to find them, they’re a detriment to safety. All of a car’s switches controls and instruments should be easy to see and easy to use when the seat is adjusted for proper posture. There is a lot of discussion these days about infotainment and navigation systems and whether they are a distraction to drivers (though some either warn you or flat-out disable certain functionality while the vehicle is in motion). As always, you make the choice about what to engage in that may distract you from the road. We hope that you make a judicious choice and pull over when appropriate.

Daytime Running Lights Studies have shown that using headlights during the day can prevent some car-to-car crashes because of a vehicle’s enhanced visibility when its lights are on. Originally popularized by GM, most automakers equip their models with daytime running lights, which are automatically activated when the ignition switch is turned on. LED daytime running lights are particularly popular on new vehicles (for aesthetics, not for functionality or safety), but with their bright white light output they are even more noticeable in daylight.

Traction Control/ All-Wheel Drive Traction control limits the power that is routed to drive wheels in order to minimize tire spin on acceleration, whereas all-wheel drive (AWD) distributes power to the axle or wheel with the most traction. Traction control and all-wheel drive are pricey features. However, they provide more control, and hence an extra margin of safety, on wet or icy roads. Dynamic stability control systems take this to the next level, teaming ABS and engine management systems together with yaw sensors to determine if there is excessive lateral acceleration and wheel slippage (aka sliding). If the computer determines correction is needed for safety, the system will help keep the car under control. While they are no replacement for prudent driving, these systems do add an extra measure of safety, best appreciated by hard-charging drivers and those who face foul weather conditions.