A method for determining if a mobile device is in a vehicle includes monitoring an acceleration of the mobile device for a time interval during a period of time. The method also includes calculating one or more characteristics of the acceleration of the mobile device during the time interval and comparing the one or more characteristics of the acceleration to a set of threshold values. The method further includes determining the state of the mobile device based on the comparison of the one or more characteristics of the acceleration to the set of threshold values, wherein the state of the mobile device includes an in-vehicle state, a non-vehicle state.