Riders in other cities make use of apps to hail cabs, but in NY the labyrinth of taxi regulations makes it difficult to discern if the apps are even legal. The issue centers on the definition of hailing a cab.
In general, yellow cabs respond to street hails, while livery cabs respond to phone requests. When a hailing request comes from a phone app, the question remains whether it is a phone call or a digital version of a street hail. The lack of an updated definition puts drivers, developers, lawmakers and VC funders at a temporary halt.