The 2014 Ford F-150 had a 4-star NHTSA overall safety rating, making it as good as or better than any pickup on the US market, except for the 5-star Chevy Silverado.

Ford's complete redesign of the truck for 2015 included a switch to an all-aluminum body that made the F-150 hundreds of pounds lighter, improving fuel economy and towing capacity. It also gave Ford the chance to go after that fifth star.

As part of the redesign, Ford added 31 new safety features, including neat things like rear seat belts that inflate in a crash, acting like a softening airbag.

The automaker's engineers also looked at the frame of the truck, focusing their efforts on what they call the front crush horn. It's the chunk of the frame that absorbs force in a frontal crash. It's crucial, because every bit of force sucked up isn't applied to the structure that surrounds the occupants. The engine compartment gets crunched so the driver doesn't.

A computer simulation of the 2015 F-150's frame during an impact. The front crash horns are illustrated in dark grey. The second wider brace (on the right) was added this year to improve side impact protection. Ford

Using computer simulations of crashes followed by physical testing, Ford's engineers decided to replace the rectangular crush horn with a new, cross-shaped design (dark grey in the GIF above) as the best balance of weight and performance. Ford says the patented, 12-corner design provides a 100 performance improvement in crushing distance (as in, it's stronger) over the outgoing version.

"We found that changing certain shapes led to a weight reduction, while also improving crash performance," says Ford Truck Safety manager Matt Niesluchowski.

Part of what makes this setup twice as effective is, paradoxically, the addition of strategic weak spots. By punching out holes and bending the metal just so, the team can ensure that the horn crushes properly and absorbs the impact, without bending or compromising the overall design of the frame.

It appears all the work paid off: The first F-150 tested, the four-door cab version, landed five stars from NHTSA. Official ratings for the regular and SuperCab F-150 models are expected later this year but Ford says this is the safest F-150 it's ever made.