Pre-2013 taxicab beacon for Washington DC taxicabs. The "CALL 911" sign was not instructing potential riders to contact 911 to book a cab, but rather was an emergency sign where, if the "CALL 911" part of the cab was flashing, bystanders should alert police because the driver is in distress.
Ben Schumin is a professional photographer who captures the intricacies of daily life. This image may be used under Creative Commons Attribution-ShareAlike 2.0. Please provide artist attribution, as well as a link to the original photo and to the license terms.