Could the city's yellow cab industry be zipping along on a collision course with the upstart Uber car service? Yes it could, and that's wonderful news for riders.

UberX -- the lower-end version of Uber -- responds to app-generated calls but not street hails. It has whacked fares in the city by up to 20 percent in a move to undercut the cost of a typical metered yellow cab ride.

This could ultimately matter plenty.

True, UberX is slashing prices for a limited time only, hoping to introduce the New York City market to its fleet and to its way of doing business.

But the yellow cab industry may be vulnerable, because it's a city-licensed monopoly that frequently fails to meet the demand for service. Fewer than 14,000 yellow cabs ply our streets, mostly in Manhattan -- an annoyingly low number that chills competition and infuriates riders.

Try getting a taxi in the rain. It helps to be an NFL tackle with no particular hang-ups about etiquette. Or try getting a taxi in the late afternoon -- when yellow-cab drivers weirdly head for their afternoon shift-change rendezvous just as the evening rush hits. You can stand on the curb and yell yourself hoarse as scores of empty cabs whiz by with each change of the light.

These are the signs of a cartel grown used to thinking about its own convenience first and the convenience of its customers second. So enter UberX. Unlike the yellow cab industry, the number of Uber cars on the street is dictated by the market and not by competition-shy owners.

And while UberX drivers can't take street hails, they can, with the touch of a smartphone, meet specific riders at designated times and places. Like all livery chauffeurs, UberX drivers are licensed by the city, fingerprinted, drug-tested and given criminal background checks. Their cars are inspected a minimum of three times a year.

It's impossible to say for certain how this new business model will ultimately fare in New York. There are many moving parts here, and much depends on the response of the medallion holders. But fasten your seatbelts.