I notice in DC that many cabs have “Call 911” on their outside dome lights. WTF? How do they manage this? “I need a cab” doesn’t sound like an emergency…
Answered in this thread:
http://boards.straightdope.com/sdmb/archive/index.php/t-462101.html
The idea is that, if the driver is being taken hostage or is being robbed or something, they can activate the light to alert people outside. It is most assuredly not their dispatch number.
Assuming you are not jesting :
The “Call 911” luminous sign is there to allow the driver to ask for outside help if his/her passengers are putting him/her in danger. The nefarious passengers can’t see the sign from the inside.
Similar features exist on buses, often using the destination display at the front of the bus.
Even passenger planes have this: a pilot whose plane is being hijacked can discretely set the transponder to 7500.
Elderly people or people with medical problems can get a bracelet to wear with a button that automatically calls 911 at the press of the button. Why not install something similar in cabs?
Then the cabbie could press a button and 911 will get called, without having to rely on outside observers to do it. If taxi has GPS, then it could be quickly located too.
The technology is certainly standard stuff by now. Compare, e.g., OnStar.
Cabs may have that technology too. Having the external sign has the additional advantages of warning people to avoid a potentially dangerous situation, and attracting the attention of any police in the vicinity (who can see the sign and react without the need for a 911 operator to react to the call, and dispatch an officer).
As others have noted above, it’s to attract the attention of the police. I don’t know anything about DC cabs – for all I know, the cab may, in addition to displaying a “call 911” light, actually transmit a signal to the police.
In New York City, every cab has a yellow light on the rear, which can be turned on by the driver, using a footswitch. If a police officer sees this light on, he’ll pull over the cab. It’s there in case the driver is being held up.
Having driven a yellow cab at night in the bad old days of New York City (early and mid-eighties), I can tell you from unfortunate experience that there’s a real need for this. Not so much today as back then (and back then, there weren’t any yellow lights), but it’s still there. Driving all over the city picking up people and driving them wherever they want to go, and collecting the fares in cash, you might as well have a lit sign on top saying “rob me, please.” Things are better now, and cabs can take credit cards, which reduces the amount of cash on hand.
These days it’s gypsy cabs who get robbed the most. Actually, it was probably always gypsies. It’s still a dangerous job.
Yep - in fact we saw this happen just 2 or so months ago - I was driving to work and saw a bus that said something like “emergency call 911” on the back. I phoned it in to 911 and followed the bus for a bit. Never did find out what happened, I went on my way once the 911 operator said I didn’t need to follow it.