The redesigned 2019 Chevrolet Silverado and GMC Sierra earned four-star overall ratings in the NHTSA's barrage of crash tests and measurements, a downgrade from the five-star rating the feds bestowed upon last year's version of the trucks.
The government agency measures safety on a five-star rating scale, and it is relatively unusual for a new vehicle to score less than five stars overall. The pickups' main rival, the Ford F-150, earned a five-star overall rating, while the latest Ram 1500 truck hasn't been tested yet. NHTSA tests look at three areas: frontal crash, side crash, and a rollover crash risk. In the Silverado and Sierra's case, they scored four stars overall in the frontal crash tests, five stars in the side crash, and four stars in the rollover crash risk test.
Five stars equate to a less than 10 percent risk of serious injury occurring in the particular crash scenario. The NHTSA takes measurements of crash test dummies following the crash test to calculate the injury probability, which is rated on a five-star scale.
With a four-star overall rating, the NHTSA says that there is a 10 to 15 percent chance of injury in either the 2019 Silverado or 2019 Sierra—far from the highest marks when knowing the star scale's measurements.
The rollover risk crash scenario is calculated rather than tested, and four stars is typical for SUVs and trucks.
In this evaluation, the NHTSA looks at a car's static stability factor, which is calculated with track width and a center of gravity's height. Wider vehicles with larger tracks have a lower probability of rolling over, as do vehicles with a lower center of gravity. The Silverado and Sierra's higher center of gravity doesn't do them any favors in the rollover risk crash test. It's worth noting the NHTSA doesn't assign a star value based on injury probability in this crash test. Instead, the star value comes from the probability of the vehicle actually rolling over after a driver loses control.