001 2015 Honda Fit
The 2015 Honda Fit. Honda Motors says the upcoming Fit, which goes on sale in the U.S. later this year, will be safer than its predecessors. Angelo Young

It’s no surprise the smallest cars on the road are more likely to be death traps in accidents compared to larger cars with more inherent structural protection. The driver of a monster SUV is simply surrounded by more stuff than the driver of glorified golf cart. But that doesn’t mean safety- and economy-conscious car buyers should just assume all minis respond more or less the same in accidents.

SparkIIHSCrashTest2
The Chevy Spark is currently the safest subcompact on the market, according to the IIHS. The government vehicle safety watchdog also gave the Spark an extra star for side collisions compared to the Honda Fit, which ranked at the bottom of the IIHS's safety list of eleven top selling models in this segment. Top: IIHS; Bottom: GM

The latest crash tests from the Insurance Institute for Highway Safety (IIHS), the 54-year-old nonprofit that supplements official government crash testing data, puts the Chevy Spark from General Motors Co. (NYSE:GM) on the top of the list for safety in this segment while the Honda Fit ranks at the bottom of the list of the popular models in the U.S. marketplace.

"Small, lightweight vehicles have an inherent safety disadvantage. That's why it's even more important to choose one with the best occupant protection," says Joe Nolan, IIHS senior vice president for vehicle research. "Unfortunately, as a group, minicars aren't performing as well as other vehicle categories in the small-overlap crash.”

The small-overlap crash test, introduced by the IIHS in 2012, mimics what happens when only part of the front end of a vehicle collides with something, like an electrical pole. Unlike front-end-collision testing from the National Highway Traffic Safety Administration (NHTSA), in which cars hit barriers head-on at 35 mph, the IIHS tests what happens when 25 percent of a vehicle’s front end behind the driver hits a barrier at 35 mph.

Overall the Spark ranked “good” for injuries, the only mini in the category to earn that ranking for lower-leg and foot injuries. It also was the only mini to rank “acceptable” (the second-highest grade) in overall crashworthiness. The Fit was the only vehicle that ranked “poor” in both categories of lower-body injuries. Check out the IIHS ranking released Thursday:

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The latest IIHS subcompact crash testing. IIHS

The NHTSA’s safety ranking is a little more forgiving, in part because of its simpler ranking system. It grants stars for each of three categories (front crash, side crash and rollover) and then gives an overall ranking. The 2013 Fit and the 2014 Spark both get four stars overall, but the Spark received an extra star for side crashes.

For its part, Honda Motor Co. Ltd. (TYO:7267) has said its 2015 Fit, which is expected to go on sale in the U.S. in a few months, will have more steel in it than its predecessors while being 57 pounds lighter and says it will attain a “good” rating for all IIHS test modes, “including the rigorous small-overlap barrier test.”

We’ll leave that up to future IIHS tests to decide.