As SUVs are classified as "light trucks" they actually have less stringent safety standards than the traditional sedan. They're also both more likely to suffer rollover accidents, and for those rollover accidents to be fatal. In short, because of the additional size and weight of SUVs (light trucks) they're more statistically safer in a crash than a sedan, but also more likely to get into a crash in the first place.
"Under the Federal Motor Vehicle Safety Standards (FMVSS), passenger cars must adhere to stringent safety regulations that set specific requirements for bumper height, impact resistance, and crashworthiness. These "crash compatibility" requirements are designed to ensure that vehicles of different sizes and types interact as safely as possible during collisions. However, due to their classification, light trucks are subject to less stringent safety standards regarding their structure and crash compatibility, posing unique hazards to both pedestrians and occupants of smaller vehicles."
https://publications.lawschool.cornell.edu/jlpp/2024/11/25/the-unchecked-rise-of-trucks-and-suvs-in-america/
SUVs are considerably more dangerous to pedestrians as well, mainly due to the increased size, the shape of the front end, and the decreased visibility in the vehicles.
https://www.vox.com/future-perfect/24139147/suvs-trucks-popularity-federal-policy-pollution
Also, interestingly consumer reports won't even compare trucks/SUVs safety with sedans because of their size. They're more likely to get into accidents in the first place because the additional weight and size mean that they just can't avoid accidents that traditional sedans would.
"You won't see any full-sized SUVs or pickups on this list, either. "Larger vehicles take longer to stop and don't handle as nimbly as smaller vehicles," he says. "A large vehicle might get into a crash that a small vehicle could have avoided."
https://www.consumerreports.org/cars/car-safety/how-to-find-safest-new-car-using-crs-safety-verdict-a3169270635/
So while your question was only about standards in the event of a crash, just overall, crashes are more likely in SUVs or trucks, but when they do happen they're slightly more safe from fatalities because larger vehicles tend to be safer in light impact crashes, especially between two vehicles.
