Driving activity is segmented into trips (travel between a start and a stop). Trips can be seen in the Trips Report and in the Vehicle Details Page.
Samsara uses heuristics to distinguish between the end of a trip and a pause in driving, e.g. at a red light. A trip is considered complete if the vehicle is stationary for 10 minutes or more. However, if the vehicle is stopped at a location in the address book, that threshold falls to 2 minutes. Engine status is not taken into account.
If your drivers are stopping at known addresses, we recommend uploading your address book to get the best user experience.