Wireless network outage affected traffic lights, NYPD license plate readers

An outage of New York City's wireless network over the weekend affected thousands of traffic lights and dozens of NYPD license plate readers. The outage also disrupted some systems in the Health, Sanitation and Parks departments.

The outage happened during a worldwide GPS update on Saturday. I.T. managers around the world made software or hardware updates in advance to prevent an outage.

The U.S. Department of Homeland Security warned the city a year ago about taking the necessary steps to prepare but the city failed to act.

Mayor Bill de Blasio on Thursday said he doesn't understand why that happened and wants to know what was missed.

The defense contractor Northrop Grumman built the network for the city and receives about $37 million a year from the city to maintain it. Fox 5 contacted the company but has not heard back.