The aim of this study is to evaluate the interaction of car passengers in side collisions. In 12 side impact tests, four newly developed side impact dummies (APROD 82, HSRI, MIRA, ONSER) were positioned at the impact side of the car, with the interacting dummy - a Hybrid II dummy - on the offside. The velocity of the impacting rigid barrier was 45 km/h. Each test configuration with each side impact dummy was repeated three times. They are compared with tests of the same configuration but without an interacting Hybrid II dummy.The kinematics of the side impact dummies are more humanlike in side impacts than those of the Hybrid II dummy which was used in a previous test program on the impact side. Each side impact dummy showed interaction effects and loads in different measuring parameters.