That’s more or less the premise of the “Eco Assist” dashboard features on the 2010 Honda Insight hybrid. Much the way many video games have heads-up displays that change color according to the condition of a character’s health; the Insight’s speedometer readout has a crescent icon that changes hue based on the driver’s acceleration/deceleration rate, glowing green when it’s most fuel efficient, but turning blue as it becomes wasteful. Like a role-playing game, the driver’s behavior is also tallied over time, and displayed symbolically — here, in the form of an ivy-ringed trophy achievement that a driver can gradually unlock with green-friendly driving. It’s sort of like Wii Fit, but for cars.