Been wondering what all those “Join the 74” signs along Roanoke City streets were all about? That’s the current number of 10th graders in the city that claimed on a recent survey they have not drank alcohol in at least the last 30 days. That’s a start says J.D. Carlin, a youth leadership specialist for the Roanoke Prevention Alliance. What’s normal says Carlin is that 10th graders should NOT be drinking alcohol. Roanoke Vice-Mayor and police chief Tim Jones helped unveil the meaning behind the “Join the 74” signs this afternoon – with the help of students.