Car Buyer Labs

Car Buying Advice, Tips, and Reviews

A woman is shown receiving keys after looking at used cars for sale.

All About Safety Ratings: Shopping Confidently for a Used Car

Shopping for used cars for sale is a clever way to put your hard-earned money to work. New cars immediately start depreciating once you drive off the lot, and they continue to decline in value over the next five years. By investing in a used car, you pay closer to the actual value of the car, truck, or SUV and can often afford a top-tier trim with comparable features and a wide range of innovative technologies.

Getting caught up in the bells and whistles, like smartphone integration and WiFi hotspots, is easy as you narrow your options. However, it’s critical—especially if you’re shopping for a family vehicle—to consider the safety and driver assist features along with the model’s safety ratings. While industry standards regulate how vehicles are built and what features are required, every car, truck, and SUV responds differently in a collision. Fortunately, safety ratings help you better understand these responses before you make your investment.

A mechanic is shown shaking hands with a consumer after the vehicles safety checks were completed.

Key Players: Who Gives the Ratings?

Two organizations are responsible for rating every vehicle each year: the Insurance Institute for Highway Safety (IIHS) and the National Highway Traffic Safety Administration (NHTSA). The NHTSA is a government organization established by the Highway Safety Act in 1970 with the mission to “save lives, prevent injuries, and reduce economic costs due to road traffic crashes, through education, research, safety standards, and enforcement activity.” While the NHTSA is part of the United States government, the Insurance Institute for Highway Safety is an independent nonprofit. Why is this a critical difference?

The IIHS was established in 1959 by three of America’s biggest insurance companies to support highway safety efforts. However, after a decade of promoting and assisting everyone else’s efforts, the IIHS reestablished itself as an independent science and educational organization. With the change, the company began focusing on crash prevention using modern scientific approaches that consider human factors, extensive vehicle research, and environmental research, like roadways and how they’re designed. Today, that approach is at the heart of the IIHS’s mission to reduce “deaths, injuries, and property damage from motor vehicle crashes through research and evaluation and through education of consumers, policymakers, and safety professionals.”

Tests: What Types of Crash Tests Are Conducted?

Most collisions in the United States fall into three broad categories: frontal, side, and rollover. The NHTSA and IIHS examine how models respond in these types of collisions, with each organization taking a unique approach. For example, where the NHTSA conducts four tests on every model, the IIHS offers more extensive testing that examines various aspects of the vehicle, its components, and its response in a collision. Here’s a closer look at those tests and how testing from both organizations provides a comprehensive picture of how a vehicle will likely respond in a crash.

IIHS Testing

IIHS started conducting frontal crash tests in 1995 and continues to do so today with three different tests: moderate overlap front and small overlap front tests on the driver and passenger side. The moderate overlap front test looks at how a vehicle responds when it crashes into a barrier at 40 mph, with 40% of the vehicle’s front end making contact with the barrier and a driver and passenger in the backseat. The passenger and driver-side tests evaluate the vehicle’s response at the same speed at the left and right corners of the car, taking into account driver and passenger-related injuries.

In 2003, the IIHS started conducting side crash tests to give automakers more insight into improving vehicle construction. This testing has led to significant advancements in the industry, leading automakers to utilize crush zones that absorb energy from a collision to protect the driver and passengers. As far as the test itself, it simulates the effect of a vehicle traveling 37 mph and crashing into a 4,200 lb barrier with a driver and passenger.

Beyond these critical tests, the IIHS conducts extensive front crash prevention tests and evaluates areas like the headlights, LATCH system, and seat belt reminders. Due to improved vehicle design, the IIHS has also phased out several tests. For example, 2022 models are the last to undergo roof strength, head restraint, and seat testing.

NHTSA Testing

The NHTSA focuses on four critical areas of vehicle safety: frontal, side barrier, side pole, and rollover. The organization’s frontal crash test evaluates how the vehicle responds when it crashes into a barrier at 35 mph, simulating a head-on collision with another car of the same size. This test examines how the vehicle responds and any related injuries to the driver and front passenger.

The NHTSA’s side barrier crash test mimics the IIHS’s side crash test but uses a smaller barrier. A vehicle is traveling 38.5 mph with a driver and passenger in the backseat on the driver’s side when it crashes into a 3,015 lb moving barrier. This mimics a situation where another vehicle speeds through an intersection and crashes into your car on the driver’s side.

Apart from testing how a vehicle responds to a side barrier impact, the NHTSA also looks at what happens when a car is impacted at a different angle or the side pole on the driver’s side. This test mimics a real-life scenario, like a vehicle that hydroplanes and hits a telephone pole on the driver’s side. During this evaluation, the car is positioned at a 75-degree angle before it’s pulled into a pole ten inches in diameter at 20 mph.

The NHTSA’s final test looks at a vehicle’s rollover resistance based on its Static Stability Factor. In other words, it looks at how top-heavy a vehicle is and how likely it is to roll over. For example, a taller SUV traveling at 55 mph when the driver loses control on a curve is more prone to rolling over than a compact sedan with a lower center of gravity and a more even distribution of weight.

A crash dummy is shown being used to conduct crash tests.

Scores: What Do They Mean?

The NHTSA scores every model using a five-star system, which the organization implemented in 1993 to help consumers make more informed purchases. The five-star system is straightforward, with a five-star rating signifying exceptional performance and the highest rating a vehicle can earn from the NHTSA. Alternatively, because the IIHS conducts many other tests, their scoring system is slightly different and falls into two categories: the Top Safety Pick awards and the individual ratings.

The IIHS rates every test as Good, Acceptable, Marginal, or Poor, with Superior, Advanced, and Basic designations. This comprehensive scoring ensures consumers have vital information about how every model performs before they make their purchase. In addition, the IIHS has added to its ratings over the years by introducing the Top Safety Pick and Top Safety Pick+ awards. These honors are given to vehicles that perform exceptionally well, earning superior and advanced ratings in most categories.

Knowledge Is Power

Purchasing a used car, truck, or SUV is an investment regardless of how much money you spend. As with every investment, it’s essential to do your homework beforehand to have all the necessary information, as this will give you confidence in your purchase. Your homework should involve looking beyond the luxuries and advanced connectivity features to focus on how the vehicle will keep you and your passengers safe. It means looking at its safety scores with the NHTSA and IIHS—two organizations committed to doing the hard work for consumers—so you know your vehicle’s crashworthiness before you sign along the dotted line.