Open Spot works by letting people who are leaving parking spots share their spots with people who are searching for parking.

Start helping others find parking, and together we’ll all save time, save gas, and reduce pollution. Like to keep score? The more open spots you mark, the more parking ‘karma points’ you’ll get.

It’s a cool idea, and could be useful if enough people around you use it. Of course, if you know the area well, you probably already know where to park, meaning the app will probably end up mostly helping suburbanites and out-of-towners find city parking. Also, if you really wanted to save gas and reduce pollution, you wouldn’t be driving.

Via Gizmodo.