Complex sentence: Moving on rough terrain was a challenge for the four SMSS vehicles deployed to Afghanistan in 2012; they could not discern between soldiers and obstacles like trees, so they mostly traveled on roads instead of complex terrain.
Split into simpler sentences: Moving on rough terrain was a challenge for the four SMSS vehicles deployed to Afghanistan in 2012. They could not discern between soldiers and obstacles like trees, so they mostly traveled on roads instead of complex terrain.