[chongli]

Yes. Anyone who has worked on conservation of momentum problems in high school physics should recognize this. Even at low collision speeds if there is a large disparity in mass between the vehicles then the lighter one experiences a lot of acceleration.

For an extreme case think of a low speed collision between a bowling ball and a ping pong ball.

[HPsquared]

It boils down to "delta-V".

In a mismatched collision, the smaller vehicle needs to withstand a higher delta-V than the larger vehicle.

Also, in many cases the bumper heights are mismatched so the larger vehicle's strong structure runs into higher, weaker parts of the small vehicle, further exacerbating the problem.