Small increases in speeds over 50 miles an hour can have huge effects on crash outcomes, according to new research from the AAA Foundation for Traffic Safety, the Insurance Institute for Highway Safety and Humanetics.

According to the new information, slightly higher impact speeds were enough to dramatically increase the driver’s risk of severe injury or death if they were involved in a crash.

“It cannot be stressed enough how big of an impact speed plays in a crash,” says Theresa Podguski, director of legislative affairs, AAA East Central. “The small amount of time you save on your trip is not worth the risk of harming yourself or others.”

To investigate the impact of speed on crashes, the AAA Foundation for Traffic Safety, in collaboration with the Insurance Institute for Highway Safety (IIHS) and Humanetics conducted crash tests at three different impact speeds (40, 50 and 56 mph).

Researchers used three 2010 Honda CR-V EX crossovers in this study, because they represent the average age (11.8 years) of a typical vehicle on U.S. roads and earned the top rating in the IIHS moderate overlap front test.

The study revealed that slightly higher speeds were enough to increase the driver’s risk of severe injury or death upon crashing. As the crash speed increased, so did the structural damage to the vehicle and forces on the crash dummy’s body.

At the 40 mph impact speed, there was minimal intrusion into the driver’s space.

At the 50 mph impact speed, there was noticeable deformation of the driver side door opening, the dashboard and the foot area.

At 56 mph, the vehicle interior was significantly compromised, with the dummy’s sensors registering severe neck injuries and a likelihood of fractures to the long bones in the lower leg.

“Higher speed limits cancel out the benefits of vehicle safety improvements like airbags and improved structural designs,” said Dr. David Harkey, IIHS president. “The faster a driver is going before a crash, the less likely it is that they’ll be able to get down to a survivable speed even if they have a chance to brake before impact.”

At both 50 and 56 mph, the steering wheel’s upward movement caused the dummy’s head to go through the deployed airbag. This caused the face to smash into the steering wheel. Measurements taken from the dummy showed a high risk of facial fractures and severe brain injury.

“Our crash test dummies are instrumented with hundreds of sensors to measure the injury risk so that we understand the scientific limits of safety and injury prevention. Understanding that the risk of serious and permanent injury becomes significantly higher in crashes beyond statutory speed limits clearly demonstrates why there are limits in the first place,” commented Jack Jensen, vice president of engineering at Humanetics.

When correctly set and enforced, speed limits improve traffic flow and maximize all public road users’ safety. Yet, when officials raise limits to match travel speeds, people still go faster. Today, 41 states, allow 70 mph or higher speeds on some roadways. Of these, eight states have maximum speeds of 80 mph or more.

A 2019 IIHS study found that rising speed limits have cost nearly 37,000 lives over 25 years. AAA and IIHS urge policymakers to factor in this danger from higher speeds when considering speed limit changes.

“Cars are safer than they’ve ever been, but nobody’s figured out how to make them defy the laws of physics,” said Harkey of IIHS.

“Rather than raising speed limits, states should vigorously enforce the limits they have. This includes using proven countermeasures like high-visibility enforcement and carefully implemented speed-camera programs to consistently and equitably enforce speed limits 24/7.”

Speed limits should not be raised or lowered only to manipulate traffic volume on a particular roadway. States are urged to use engineering and traffic surveys when setting maximum speed limits.

This study is the second part of the AAA Foundation for Traffic Safety research examining the effect of posted speed limit changes on safety. In the Foundation’s first study, traffic engineers were asked how posted speed limits are set and what factors they consider in changing them.

The research tests were conducted following the same protocol that is used for the IIHS moderate overlap evaluation; only the speed was varied. With a test dummy representing an average-sized male in the driver’s seat, the cars were crashed with 40% of the vehicle’s front on the driver side overlapping the barrier.

IIHS has been conducting this type of test, which simulates a head-on, partial-overlap impact between two vehicles of the same weight and size traveling at the same speed, since 1995. Since 2013, 100 percent of new vehicles have earned a good rating when tested at the 40 mph impact speed.