Do you point your shoulders at 'em while still riding? Sometimes I can get 'em to back off before they're even in the street (but that could be better training too).
Marking our bike club ride we had one come out and we stopped, and that critter paused from ahead of us and kept looking back... looking back... took its owner 3-4 minutes to get him close enough to grab (alas, I suspect because Dudley knew he'd get smacked around some), while he told us that yes, he generally kept the dog in 'cause he'd run with cyclists for miles. Unfortunately, he wanted running *and* playing and somebody would be goin' down eventually...