Alan Ruck is thankful to escape his scary car crash without so much as a scratch on him ... and he's giving credit to a higher power no one else was killed in the accident.

The "Succession" star was spotted leaving a convenience store Thursday in Los Angeles when he was asked how he was doing after Tuesday's crash when he smashed his Rivian truck into a Hollywood pizza place.

Alan was limping with a sleeve over his left knee, but he says it's just a sign of his old age and not related to the crash. The actor says he's fine and thanks God no one was killed in the incident.

As for the online chatter ... Alan's well-aware folks are comparing the truck crash to his famous Ferrari crash scene in "Ferris Bueller's Day Off."

TMZ broke the story ... Alan crashed into Raffallo's Pizza at the intersection of La Brea Avenue and Hollywood Boulevard in an incident that is now under police investigation.

Video shows Alan's truck lodged into the side of the brick building ... and surveillance appears to show his Rivian colliding with another vehicle from behind before flying through the intersection and crashing.

Our sources told us two people were injured in the crash, but they were both breathing and conscious and are expected to be OK.