Yes, iDriveSure does use cellular data when not connected to Wi-Fi, which is mostly when you are driving. To function as designed, iDriveSure taps into various third-party API services for posted speed limits, weather, traffic, roadside assistance, etc. which calls over the network. This data exchange is very minimal. Try not to open the app when it is not connected to Wi-Fi, to minimize the use of your data plan, and let it run in the background.