Source: Washington Post 
Date:  February 25, 2012

About 10 a.m. Tuesday, the District Department of Transportation plans to cut power to the traffic-control signals at Dupont Circle for several hours so they can be upgraded. They will be back on in time for the afternoon rush, DDOT said.

During the outage, watch for the traffic-control officers directing drivers through 19th Street, P Street, New Hampshire Avenue, Massachusetts Avenue and Connecticut Avenue NW. It would be best to avoid this busy area during the disruption.