When the Insurance Institute for Highway Safety tested the 2015 F-150 pickups for crash safety it really got your attention, and Ford’s too. Now, they’ve tested all the full-sized pickup trucks to see which ones are safest, and which ones aren’t so much.

In the latest round of IIHS crash tests for full-size pickups by the IIHS, only one truck brand earned good ratings in the brutal small-overlap crash test, and only three of the seven got an acceptable rating. Several of them only achieved marginal results, and as they found out it’s not all about the brand name but the cab style.

Starting with the Ford F-150 that made news last year with its all-aluminum body, the 2015 model performed well in the full-sized crew-cab, but didn’t at all do well in the super-cab model. This is because for 2015 Ford had installed additional bracing in the larger cab that made it more resistant to wheel intrusion.

For 2016, Ford has added the same bracing and some additional reinforcements for all 2016 F-150 cabs that have helped now both the crew-cab and extended-cab models to achieve a good rating in the crash testing.

In fact in side-by side tests you can see how well the 2016 extended-cab performs in the test compared to the 2015 model. The additional bracing added for 2016 seems insignificant but it shows how well even small changes that don’t cost a lot can make a world of difference in safety.

To see how the other brands compare, both cab sizes of the Chevrolet Silverado and GMC Sierra were tested in addition to the Toyota Tundra and RAM 1500. And in these tests it was shown again that cab configuration has a lot to do with how they perform in a crash.

The Chevrolet Silverado and GMC Sierra extended-cab was first up in the test, earning an acceptable rating in the small-overlap crash. Though the cab structure held up somewhat good, significant wheel intrusion through the floor was a major contributor to possible leg injuries.

The larger crew-cab Silverado and Sierra while similar in design showed that even dimensional variations in length and weight differences can change how the vehicle performs in a crash. Wheel intrusion into the floor board and cab protection were significantly worse than the smaller cab, earning a marginal rating in the tests.

A similar story was found in how cabs perform with the Toyota Tundra. The extended-cab Tundra earned an acceptable rating in the small-overlap crash with wheel intrusion through the floor board being a major issue.

In testing the larger crew-cab Tundra, the cab crush and wheel intrusion were more severe causing it to earn only a marginal crash test rating. In these tests, the likelihood of severe lower leg injuries were significantly higher.

When it came to testing RAM, the results for both cabs were equally the same.

With both cab sizes of the RAM 1500, the tests shows they were the worst performing among all brands earning marginal ratings. Not only was wheel intrusion into the passenger compartment very sever, but the cab structure itself was able to crush in on the passenger space.

In both cabs the front door pillar, the dash panel, and the steering column was allowed to push significantly back into the driver. This compounded the severity in the crew cab as when the steering column moves to the side, the airbag no longer properly controls the occupant, allowing them potentially to contact hard parts.

The IIHS will be testing the 2016 Nissan Titan and Honda Ridgeline later this year.

IIHS Small-Overlap Results:

Ford F-150 SuperCab: Good

Chevrolet Silverado 1500 Double Cab: Acceptable

GMC Sierra 1500 Double Cab: Acceptable

Toyota Tundra Double Cab: Acceptable

Chevrolet Silverado 1500 Crew Cab: Marginal

GMC Sierra 1500 Crew Cab: Marginal

Toyota Tundra CrewMax: Marginal

Ram 1500 Quad Cab: Marginal

Ram 1500 Crew Cab: Marginal