By early next year, hailing a yellow cab in New York City could
be as easy as whipping out a smartphone and pressing a button.
That is, unless the companies that run the city's livery fleets
succeed in blocking a rule change in a key vote next week.   TLC
Chairman David Yassky, one of four mayoral appointees to the
commission, was scrambling this week to secure a fifth vote to
pass the new rules, which would permit the use of apps, with
conditions—including requiring that each app use data and
calculate fares using the existing meter system.  The key
objection from the livery industry, as well as some who own
yellow taxi medallions, is that permitting the use of apps, like
Uber and Hailo, will break down the existing rule that forbids
yellow taxi drivers from "prearranging" rides with their
customers.  The prearrangement rule dates back to the banishment
of radios taxicabs in the 1980s, a move that required cabbies to
seek out their fares among the crowds trying to hail them from
the sidewalk, and also stimul