The District Department of Transportation is replacing 67,000 antiquated or defective streetlights in eight city neighborhoods.

The work, which is in its earliest stages, primarily will modernize lighting networks that operated like old Christmas tree lights: When one went out, entire neighborhoods were plunged into darkness.

The new lights will be more bright, reliable and attractive, officials say. The new systems will also save the city money on maintenance.

The neighborhoods slated for the replacements include areas of Mount Olivet Road in Northeast, C Street in Southwest, and Mount Pleasant, Woodley Park, the Rockwood Parkway and Constitution Avenue areas in Northwest, according to Bill Rice, department spokesman. In addition, lights will be replaced around M and North Capitol streets and in the upper part of 16th Street NW.

Altogether, 80,000 lighting units will be replaced, including tunnel and underpass lighting.

New manholes, conduits and cable will feed the new lights, and existing streetlight poles and fixtures will be replaced. All the roads and alleys that are torn up to install the new lights will be resurfaced curb to curb, the department said.

The project will cost about $7.1 million, according to department data. Work on all projects will take just over a year. Some are scheduled to be done before Thanksgiving.

All but one of the streetlight systems that are being replaced are series circuit streetlights, in which one outage knocks out all the other lights on the circuit. The new systems use parallel circuits. The 16th Street area has had an old parallel system, which is being replaced.

"DDOT is pleased to start replacing these circuits that are such a problem across the District, especially in some of our residential neighborhoods," DDOT Director Dan Tangherlini said in a statement.

Rice said department officials met with residents in each neighborhood to determine streetlight style and intensity.

Woodley Park resident Sally MacDonald started pressuring the city to fix the problem a decade ago. In those days, the lights would stay out as long as two weeks, leaving residents in the dark, she said.

The streetlights in Woodley Park go back as far as the 1920s, when the homes were built, MacDonald said. She started chronicling each day of darkened streets in what she calls the "Diary of Darkness," disseminated by e-mail.

The darkness created serious hazards, as neighborhood streets became more like obstacle courses at night. Uneven pavement, protruding branches and wet leaves, all undetectable in the dark, were constant hazards citizens had to be aware of, said MacDonald, an Advisory Neighborhood Commission representative.

"These are things we learned to live with," she said.

All the while, MacDonald and others pressed the city to provide consistent lighting and prompt service when the lights went out. "We're paying for [streetlights] and we want to have them," she said.

In Woodley Park, the city has agreed to replace the old lights with newer versions that will be uniform in size, color and style. The new lamps will be brighter, and there will be more of them, to ensure that no places are inadequately lit, MacDonald said.

Her persistence earned her the nickname "streetlight lady. " It is a name of which she is proud.