The DriveGain app uses the iPhone's built-in GPS system to calculate the vehicle's speed and rate of acceleration and deceleration. The visual displays include a recommended gear indicator and some sliders that drivers try to keep in the green. In addition, the app calculates fuel consumption, CO2 emissions, fuel cost per mile and much more. By following the on-screen cues, DriveGain claims that it can help users save hundreds in fuel while reducing CO2 emissions by up to 660 kilograms per year.
The DriveGain app is currently only available for manual transmission vehicles, but automatics will be supported soon. The apps database has over 16,900 different cars to choose from and can be used on the iPhone 3G and 3GS, as well as on the iPod Touch and iPad. iPhone 4 support is coming soon. To download the app, click here.