I did a few searches on the forum and they turned up nothing confirming or denying the need so I here I post!
Subject pretty much explains it all, just wanted some confirmation if you need an Adventure Pass to park at the Bradford Ridge bridge dirt parking lot?
From what I can gather from the Adventure Pass web site that this parking lot is in San Bernadino National Forest and is not in a "Fee Area - HIRA" (place that you need an Adventure pass).