Let's say you were walking through a dark hallway, which you were very cautious, then you sensed a long tube of steel that could have tripped you, but luckily it didn't. And you say:
What the... I am lucky! I could have tripped by that steel.
Or
What the... I am lucky! I could have been tripped by that steel.
Which one is correct?
You're actually asking about active versus passive voice: the second sentence is correct because the steel is acting (could have been acting) on you; the first sentence should be corrected to "The steel could have tripped me" so that the steel is acting (could have acted) on you.
Once corrected you have a choice between these two constructions - either the steel acting on you (active voice), or you being acted on by the steel (passive voice).
