Gov. John Hickenlooper on Tuesday issued an executive order requiring the adoption of low-emission vehicle standards by 2025, with the first steps in developing the program ready by the end of this year. The idea is that relying on available technologies in clean-energy delivery and using cost-effective strategies will boost the state’s chances of meeting its goal of reducing greenhouse gases by 26 percent in that time frame, Hickenlooper’s office said in a statement. “Colorado has a choice.