What aspect of vehicle safety does the side impact test primarily assess?

The side impact test primarily assesses the effectiveness of vehicle safety features designed to protect occupants during a side collision. This includes evaluating the deployment and performance of side airbags. Side airbags are crucial for cushioning the occupants in the event of a side impact, reducing the risk of injury by providing a protective barrier against the intruding object and preventing occupants from making contact with the vehicle's interior.

While the other aspects listed are important for overall vehicle safety, they are not the primary focus of the side impact test. Frontal collision protection pertains to the vehicle's performance during front-end crashes, roof strength relates to how well a vehicle's roof can withstand forces during a rollover accident, and overall structural integrity encompasses how well the entire vehicle can absorb and manage crash forces in various types of collisions. Thus, the side impact test is specifically designed to measure the protective capabilities of side airbags and other related safety features in side-impact scenarios.