DETROIT --- Fuel-efficiency gauges, first made popular in gas-electric hybrid vehicles, are starting to appear in non-hybrids. Such a gauge shows drivers what their mileage is at any given moment and informs them when they are driving most efficiently. The gauge helps educate drivers on how driving habits can impact fuel efficiency. Nissan started installing a fuel-efficiency meter into the instrument cluster of certain Nissan and Infiniti cars, pickups and SUVs, and plans to phase them into the entire lineup, USA Today reported. Ford Mustangs, Edges and Fusions have a fuel-efficiency meter in the optional information center part of the instrument cluster. Fuel efficiency is indicated using a bar chart like the kind that measure signal strength on cell phones. Chrysler and GM has begun including displays that show when cylinders are deactivated in the gas-saving systems of some V-8 and V-6 engines. Chrysler vehicles display the message "fuel saver mode" on the instrument panel. Some Honda models have a dashboard light that illuminates when gas mileage is at its peak. Meanwhile, Toyota is studying whether its non-hybrid customers would make use of the gauges, USA Today reported.