Officials expect to cut the county's electric bill by about $140,000.
The program began as a budget-cutting measure in 2009 and this year, officials have added more streetlights.
Transportation and Engineering Department spokeswoman Connie Deane says cutting streetlights has not resulted in an increase in traffic accidents.
Lights are left on at major intersections and near shopping centers.
The lights will return to normal operations when daylight saving time ends November 6.