The Insurance Institute for Highway Safety (IIHS) took a look at the roof strength of five different models: The Nissan Frontier and its platform mate, the Suzuki Equator; the Ford Ranger; the Dodge Dakota; the Toyota Tacoma; and the Chevrolet Colorado.
Only the Frontier and the Equator were rated as "good" by the agency, which looked at models from several different years. In the case of the Frontier/Equator, the models in question were 2005-2010 (Frontier) and 2009-2010 (Equator, which didn't hit the market until 2009). The Frontier and Equator were the only ones to earn that rating.
IIHS took a peek at the 1999-2010 Ford Ranger, and that truck was deemed "acceptable" by the agency. But the 2005-2010 Tacoma and Dakota models, along with the 2004-2010 Colorado models were all branded "marginal". There are four ratings: "Good," "acceptable," "marginal," and "poor."
In order to measure the strength of the roof, according to the IIHS' Web site: "A metal plate is pushed against one corner of the vehicle's roof at a constant speed. The maximum force sustained by the roof before 5 inches of crush is compared to the vehicle's weight to find the strength-to-weight ratio. This is a good assessment of vehicle structural protection in rollover crashes. Each model is rated based on our measured curb weight of a vehicle with typical engine, transmission, and equipment options. However, when the same model is available in a configuration over 10% heavier than the typically equipped vehicle, a separate rating is assigned."
Considering the potential for rollover in a vehicle like a pickup truck, this isn't exactly good news.