Originally Posted by
New Yorker
No, there's just one set of brakes, like on any other bike. (Well actually, sometimes you'll find "two" sets of brake handles: the regular ones on the drop portion of the bars—plus a set of small, cheap auxiliary handles—called "safety handles"—connected to the regular brake handles. These so-called "safety handles" can be reached from the upright "rest" position on the tops of the bars. They aren't very good and they're anything but safe. I don't even know if they're still around, but once upon a time they were quite common.)
Not quite true.
'Interrupter' or cross levers can be mounted on the bar tops. Many tourists / commuters use these, along with cx racers, and a friend who rides fixed and likes a brake in the upright position.
The brakes you speak of were popular on 'ten speeds' and worked by operating the main brake lever from the tops. Cross levers actually pull the same cable, and can be used as your primary lever.