Originally formed as a power trio by Cleveland-born drummer Tyler Bond and guitarists Mike Lindner and Alex Stanton, the now-Pittsburgh-based 28 North steers into new territory with the addition of bass player Jonathan Colman. All four guys are school-bus drivers — an ideal day job, since it allows for weekends and nights off . . . as well as a pretty flexible summer schedule. On its new album, Mystery, 28 North plays guitar-fueled rock, fused with three-part harmonies inspired by hairy hippies like the Allman Brothers and Crosby, Stills, Nash & Young. All three original members write and sing, which spreads the group in different directions. "Vacant Road" mixes Grateful Dead's patchouli-scented jams with some hard rock, while Mystery's title tune is a southern rocker with a hook-stuffed chorus. With this kind of momentum, it's only a matter of time before some kids in Pittsburgh will have to find another way to get to school.