CHRIS BROWN DANGEROUS SKID MARK PROBLEM ... Neighbors Call Cops

Chris Brown's neighbors think he's terrorizing his ritzy quiet neighborhood, and it could spark yet another criminal investigation -- this time for reckless driving and speeding.

According to law enforcement sources ... Chris' neighbors in Agoura, CA (think Calabasas, but sleepier) have called police about 20 times in the last few months to complain about cars doing donuts and blazing down the street. They point to dozens of skid marks as evidence of the joyrides.

As for why Brown is getting fingered ... we're told neighbors recognize his exotic sports cars and think it's gotta be him or his friends.

For now, we're told cops will beef up patrols in the area to nab whoever's laying down the rubber.