The city of Denver has unveiled a “Driving Change” pilot program designed to reduce vehicle greenhouse-gas emissions by encouraging drivers to ease off the lead foot. Starting in May, 400 public and private Denver vehicles, including that of Mayor John Hickenlooper, will have a device installed to monitor time spent braking, idling, accelerating, and speeding. Analyzed results and personalized recommendations for reducing fuel consumption will then be posted on the internet. Vehicles account for approximately 30 percent of Denver’s greenhouse-gas emissions, and the program hopes to cut fuel consumption 20 percent among Driving Change participants.