A plan to cut costs and reduce carbon emissions in San Francisco could result in the city's vehicle fleet being cut by 20 percent, according to the San Francisco Examiner.

The plan by Mayor Gavin Newsom would require departments to reduce the number of passenger cars and trucks used by their employees by 20 percent by 2014, which would be 5 percent annually. Those numbers are included in legislation introduced to the board of supervisors.

Newsom recently announced a partnership with City CarShare as an alternative to having to purchase new vehicles and be able to reduce San Francisco's fleet size. Newsom said the legislation would encourage greater use of municipal and city CarShare programs.

Newsom has taken various incremental steps over the years to transform the fleet into a greener operation with increased oversight of vehicle use. Under the legislation, department heads would have to submit to the board of supervisors' budget analyst a report detailing how they are complying with the mandate.

The city, which has been criticized for inefficiencies, abuse and waste in its vehicle fleet, is rolling out new software that will track vehicles' mileage, gas and time running. The city's fleet has 1,591 passenger cars and a total of 2,697 vehicles, which include pickups and vans. With other types of equipment such as trailers and trucks, the fleet has an inventory of 6,881 vehicles or pieces of equipment. 

The legislation would require the removal of all vehicles that are 12 or more years old. That would have to be met by 2014.