DENVER – Castle Rock's air became a little cleaner last week, when the Town's first two hybrid vehicles hit the streets on Nov. 15, according to denver.yourhub.com. The 2008 Ford Escapes will be used by Utilities Department employees for water-monitoring and other seasonal purposes. The sport-utility vehicles operate on both electric and gas power, with on-board computers that monitor the vehicles to decide the most efficient power mode. Electric power is used mostly at low speeds and in stop-and-go traffic, and gas power at higher speeds on highways. The vehicles will get 27 to 34 mpg while driving in the city and 26 to 29 mpg on the highway — a 32 percent improvement over their gas-powered counterparts. The two new SUVs soon won't be the only fuel-efficient vehicles the Town has in its fleet, according to denver.yourhub.com. The town plans to replace three older vehicles used by the Information Technology Department with one new hybrid vehicle. In addition, the five new Ford Crown Victorias planned for purchased in 2008 for the Police Department will be flex-fuel E-85 vehicles. The Public Works Department is in the process of developing a five-year "green fleet" policy to address the use of flex fuel, hybrid, biodiesel, and other technologies to achieve lower operating costs, improve fuel efficiency, and yield environmental benefits. The policy still is being researched and reviewed by the Public Works Commission and Fleet Advisory Committee. It eventually will be presented to the Town Council as part of a Town-wide effort to become more environmentally friendly.