Mayoral candidate Rahm Emanuel called today for "a complete inventory" of city-owned vehicles, saying no one knows for sure how many of the cars exist. According to Emanuel's campaign, the Chicago city budget spends $100 million on these vehicles, plus another $30 million on fuel.

During a news conference this morning, Emanuel said the city could save $5 million by making changes to the program, including managing its vehicles more like a Zipcar service. Currently there is a shared/lease agreement that allows city workers to take some of the vehicles home.

Emanuel also proposes other "green" measures, such as using natural gas for city cars and encouraging city workers to use mass transit whenever possible. He says the federal stimulus bill provides funds to convert eight gas stations to natural gas and he'd like to see city cars take advantage of that fuel source.

Emanuel promised to do the inventory within the first 120 days of his administration. He says the city will save $5 million.