NHTSA Crash Results for 2006 Honda Insight
NHTSA Crash Results for 2006 Honda Civic Hybrid
It is also important to understand these ratings. The frontal crash tests that are done are meant to similate a head on collision of 2 similar vehicles at 35 miles per hour. If the other vehicle is larger, the chance of injury most likely increases. In general, a 4 star rated Insight is no where near as safe as a 4 star rated large SUV in a frontal collision.
Here is the official explanation.
In summary, if 2 Insights have a head on collision at 35mph, there is an 11 to 20% chance for each driver that they will sustain a serious injury. If the head on collision is with a larger vehicle (almost guaranteed with an Insight), this chance of serious injury will increase.