I actually ran into a 3-1/2 inch tall Traffic Island on the Drivers side and it did no damage at all to my Lower Control arm. The force was enought that it dented bot sides of the Front Wheel Rims, nearly tore my Rear Traliling Arm in half and Bent up the Rear Wheel.
After replacing the no good Wheels and broken Trailing Arm the Car functioned normally; no Steering Problems, no uneven Tire Wear Issues. So I concluded that the Lower Control arms were not bent or otherwise damaged.
A year later my Lower Control Arm Bushings rotted out and they needed replacement; but even the old Busings survived the Impact with the Island.

I have never read on any of the forums where a Lower Control Arm broke. And, I assume since mine survived a hard impact that they are extremely tough.

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84 300D, 82 Volvo 244Gl Diesel