Step 1: Build the clinical picture. There is a clear precipitating trauma (the accident two months ago) and the symptoms cluster around that memory - recurrent dreams of accidents, mental replay of the scene at the location, and active dread of returning there.
Step 2: This trio - intrusive re-experiencing, avoidance of the reminder, and a triggering traumatic event - is the diagnostic core of post-traumatic stress disorder. The hallmark is that past stressors intrude into the present through nightmares, flashbacks and reliving experiences.
Step 3: Compare the alternatives. An adjustment disorder is a less severe, non-specific reaction to stress without flashbacks. An anxiety disorder is generalised, free-floating worry rather than trauma-anchored intrusions. OCD centres on repetitive obsessions and compulsions, not re-living an accident. The trauma-linked re-experiencing and avoidance make PTSD the answer.
\[\boxed{\text{PTSD}}\]