"Whereas the century-old system now in use relies on block signals with colored lights alongside the track to tell operators if they're too close to the train ahead, CBTC uses radio signals to locate all of the trains on the line. With this information, on-board computers can calculate the distance between trains precisely and in real time, letting operators run trains closer together without compromising safety.
With more trains per hour, wait times will diminish and trains should be less crowded - allowing for increased ridership as the experience of riding the subway becomes more convenient and pleasant. Adding just one train per hour adds space to move another 2,640 people. That translates to fewer times waiting while a packed train goes by, and fewer elbows in your ear when you board."
Thanks to Georgia Bullen