Blue Zone

The "Blue Zone" is the area in lower Manhattan that has a blue line near the curb. Parking is not allowed Monday-Friday 7 a.m. to 7 p.m. The fine for parking here is $65, but don't risk it - cars are frequently towed as well.

http://www.nyc.gov/html/dof/html/parking/park_tickets_violations.shtml
Parking a vehicle within the area designated as The Blue Zone, Monday through Friday 7AM-7PM. The Blue Zone is bounded by the northern property line of Frankfort Street, the northern property line of Dover Street, the eastern property line of South Street, the western property line of State Street, the center line of Broadway and the center line of Park Row.

8 September 1984, New York Times, pg. 25:
Ban on Parking
To Be Enforced
Around Wall St.

A Blue Line at the Curb
to Mark Illegal Zones
By DAVID W. DUNLAP
(...)
So by late October the Transportation Department will turn the area bounded byBroadway and Wall, South and State Streets into a "Blue Zone," with blue traffic lines painted on the roadway to make it obvious where cars cannot park. Parked cars will be banned from 7 A.M. to 7 P.M., Monday through Saturday.
(...)
The blue lines, each about four to six inches wide, will be painted parallel to curbs, a foot or so into the street.

11 December 1989, New York Times, "Seeking the Hot Night Spots? Ask a Tow Truck Driver" by Marvine Howe, pg. B5:
The city's most successful tow operation is the Blue Zone Program, which was established five years ago in the narrow winding streets of Lower Manhattan, where No Parking signs were always being knocked down by trucks or stolen. It was decided to paint blue traffic lines in the street, parallel to the curb, indicating a ban on parking and loading from 7 A.M. to 7 P.M., from Monday to Saturday.

''Illegal parking in the area has been reduced by two-thirds and so at the request of the business community, we decided to double the Blue Zone,'' Commissioner Sandler said. The Blue Zone ran east of Broadway from Battery Park to Wall Street and has now been expanded north to the Brooklyn Bridge.