Real-life crashes with cars fitted with on-board crash pulse recorders were used to study the influence of their collision partner, in both two- and single-vehicle crashes, on crash severity and injury risk. The crash severity was lower in single-vehicle crashes compared with two-vehicle crashes. Both average change of velocity and mean acceleration were lower and average pulse duration was longer in collisions with deformable objects compared with collisions with fixed objects. In frontal two-vehicle crashes the average change of velocity in crashes with passenger cars was 21.3 km/h, while it was 35.8 km/h in collisions with trucks. The difference corresponded to an increased average risk of MAIS2+ injury with almost 5 times. The corresponding values for mean acceleration were 6.3 g and 8.8 g respectively, which corresponded to a doubled risk. In rear-end crashes the average change of velocity in crashes with passenger cars was 9.8 km/h, while it was 16.3 km/h in collisions with trucks. The corresponding values for average mean acceleration were 3.7 g and 4.4 g respectively, meaning a doubled average risk of long-term whiplash injury symptoms. In frontal single-vehicle crashes the average mean acceleration in collisions with deformable objects was 4.5 g and in collisions with fixed objects 6.2 g. The increase corresponded to an almost three times higher average risk of an MAIS2+ injury.