Are these apps able to track location and accelerometer data from the background? Or does this only apply to people who open something like GasBuddy while driving the car?
For GasBuddy, specifically, it was used for an opt-in feature known as "Trips" whose purpose was to show you driving insights such as those mentioned in the article (hard braking, hard turning, hard acceleration). Not enabled by default and looks to have been removed at some point.