The report by the US Insurance Institute for Highway Safety says that in a two-vehicle crash with a smaller car, the occupants of the SUV are more likely to be killed than are the people in the car.
The report is based on a study of US highway traffic fatalities during 2002 and 2003 involving vehicles made from 1999 through 2002.
Seven percent of the people who were killed in two-vehicle SUV-car crashes died in cars, but 10% of the fatalities occurred in the SUVs.
One possible reason is that more people tend to ride in the bigger SUVs, thereby putting more of them at risk in a vehicle crash.
Another possibility is that SUVs, with their higher centres of gravity, are more prone to tipping and rolling over in a crash.
Also, many people travelling in SUVs believe that the large size of their vehicles protects them and thus eliminates the need for wearing seat belts.
That can be a fatal assumption, especially in a rollover crash, according to the IHHS.
The report goes on to state that vehicle to vehicle crashes are not the main problem for 4x4 drivers - walls, trees, buildings, soft road shoulders and steep embankments are bigger threats, because most US highway traffic fatalities result from single-vehicle crashes - accounting for 42% of the car deaths studied by the institute, and 63% of the fatalities in SUVs.
"The extra risks posed by the incompatibilities between cars and SUVs are real, but it's important to note that two-vehicle crashes with SUVs aren't the cause of most car occupant deaths," Brian O'Neill, IIHS president, said in the report.
"People riding in cars are far more likely to be killed in single-vehicle crashes than in collisions with SUVs."
Having said that, O'Neill notes there is still a need for motor manufacturers to make their pickups and SUVs more compatible with cars and smaller vehicles, and to make all vehicles in general more compatible with pedestrians.