The service reductions are part of BART's effort to eliminate its estimated $310 million budget deficit over the next four years amid an ongoing decline in ridership, state funding and sales tax revenue.
The reductions were approved by the transit agency's directors when they approved the fiscal 2010 budget on June 11 and are finally taking effect.
The reductions mean that BART will return to having train service every 20 minutes on weekday evenings, weekends and holidays. There's been a 20-minute interval between trains during off-peak hours during most of BART's history, but on Jan. 1, 2008, the transit agency reduced the interval to 15 minutes for the first time.
The other cost-cutting measure is to have only one route serving the San Francisco Peninsula during off-peak hours. Currently, there are two routes during all service hours.
Other measures that BART officials have taken to try to reduce their budget deficit are raising fares, implementing parking fees at more stations and getting concessions from their labor unions.