If you're heading home to North Oakland from Codornices Park at this hour, you'd be wise to have a designated driver. Anyone who regularly drives along 51st Street late at night may have noticed it's usually staked out by at least one roaming CHP car. According to those in the inglorious biz of hunting for drunks, meandering coppers like to exit Highway 24 at 51st and head east toward Moraga Avenue. Once there, they either head north and follow Moraga Avenue to Highway 13, or cut south down Piedmont Avenue to get to I-580. Of course, patrol cars circle this loop in both directions, making it a well-worn path. Drivers who want further evidence can stop by Gaylord's Cafe Espresso, located in the middle of Piedmont Avenue and, as it happens, in the middle of the loop. On weekend nights, the ChiPs arrive by cruiser and motorcycle, and have made the spot a happy meeting ground. So don't forget to stop in and say hi. Just make sure there's nothing stronger than coffee on your breath.