One of the most frustrating things for me to observe are people in the streets uselessly trying to hail a taxi, either by a) standing with an arm outstretched a la Our Lady of Liberty or b) frantically flailing their arms, when there is either no taxi in site or there are no taxis which are both unoccupied and on duty. I am convinced that very few understand the roof light system in use and its permutations. However, most have better things to do than study the New York City Taxi and Limousine Commission (TLC) rules and regulations files, which run hundreds of pages. So, as a former New York City taxi driver, let me extract the most salient pieces that actually impact the use of taxis, including roof lights.
On the roof of every taxi, there is a 4 digit taxi license number. When lit, the taxi is available, when unlit it is occupied. On either side, there are the words "off duty." When lit, technically the cab is off duty, typically heading back home; when unlit, the cab is available for hire or hired. What no one explains is that these lights can be lit or unlit in all four combinations and their meanings. So in the spirit of Pascal's Wager, I offer:
1) Number lit, Off Duty unlit: This is your main target. The taxi is on duty and unoccupied/available.
2) Number lit, Off Duty lit: Off duty and unoccupied. This is the thorny one. Technically the driver can pick you up if your destination is on route to his garage or home. If you are aggressive and approach a driver who is headed roughly in your direction, he may oblige. However, this is also the scam setting - many drivers will do this in order to be selective about who they pick up and where they will go, a violation of TLC rules.
3) Number unlit, Off Duty lit: The taxi is occupied as a result of condition 2.
4) Number unlit, Off Duty unlit: Typical occupied condition. The taxi is on duty and has a passenger.
Rule of thumb - keep an eye out only for taxis with the center number lit, and in the case of those also with the Off Duty lit, try to grab their attention and negotiate.
Another important thing to understand is that a yellow medallioned NYC taxi must take you anywhere you want to go in the five boroughs of New York City and by any route you choose. The women in the photo were heading to Brooklyn. The first cab they approached turned them down after they indicated they wanted to go to Brooklyn. It is not necessary to ask a driver on the street if he or she will go to your destination. Get in and tell him where you want to go. In the event of any refusal or other problem, make a note of his ID number, call 311 and report him.
From the TLC website:
(a) A driver shall not seek to ascertain the destination of a passenger before such passenger is seated in the taxicab.
(b) A driver shall not refuse by words, gestures or any other means, without justifiable grounds set forth in §2-50(e) herein, to take any passenger to any destination within the City of New York, the counties of Westchester or Nassau or Newark Airport. This includes a person with a disability and any service animal accompanying such person.
I hope this mini taxi guide will keep you from unnecessary flailing and hailing :)