After a highway near-miss, what to look for in a defensive driving course

[ScottEG]

I recently had a close call on the highway where someone merged into my lane without looking, and it made me realize my reactive driving habits aren't enough. I'm considering taking a defensive driving course to improve my anticipation and hazard perception, but I'm not sure what to look for in a quality program. Are there specific techniques or mental frameworks taught in these courses that genuinely change how you scan traffic and manage space around your vehicle, or is it mostly a refresher on basic rules? I drive a compact car for a long daily commute, so practical strategies for sharing the road with larger vehicles would be especially valuable.