The Infiniti G35 is the worst performer, the study says, having sustained nearly $14,000 in damage in a series of 4 tests conducted at 3 and 6 mph.

The Saab 9-3 was the best, sustaining $5,243 damage. Only three cars sustained less than $6,000 damage, while four would cost more than $10,000 to fix.

There are multiple problems, the report says, first of which is bumpers on colliding vehicles often don't line up vertically so they don't engage. Even some that do line up don't stay engaged during an impact.