Rey Maualuga is very lucky to be alive today ... 'cause TMZ Sports has obtained crash-scene photos that we're told show the ex-NFL star's ride T-boned a parked car straight into a tree Wednesday.
Maualuga was arrested in Villa Hills, Kentucky ... after cops say he drunkenly plowed through yards and mailboxes and then slammed into a car in his white Mercedes.
And, in photos of the aftermath of the crash, you can see just how fortunate Maualuga was to have avoided tragedy.
The pics show damaged mailboxes in the neighborhood, tire marks in people's grass, and a mangled Mercedes that appears to have hit a Hyundai so hard, it wedged it into a neighbor's tree trunk several yards away.