A method for asset tracking using an asset tracking device, the method comprising: an asset tracking system performing the steps of: detecting (310; 410) a trigger to perform a co-location check; in response to the trigger, determining (320; 420) the asset tracking device is co-located with a carrier en route to a destination by: determining a route of the carrier from an origin of the carrier to the destination; receiving a plurality of location updates from the asset tracking device; determining whether the plurality of location updates are within a threshold distance of the route; and determining the asset tracking device is co-located with the carrier when one or more of the plurality of location updates are within the threshold distance of the route; determining (330; 430) a low power duration; and causing (340; 440) the asset tracking device to enter a low power mode for the low power duration; and the asset tracking device performing the steps of: transmitting the plurality of location updates to the asset tracking system; receiving a message from the asset tracking system, the message comprising a low power instruction and the low power duration; entering the low power mode in response to the low power instruction; and exiting the low power mode in response to expiration of the low power duration and exiting the low power mode in response to detection of an interrupt. an asset tracking system performing the steps of: detecting (310; 410) a trigger to perform a co-location check; in response to the trigger, determining (320; 420) the asset tracking device is co-located with a carrier en route to a destination by: determining a route of the carrier from an origin of the carrier to the destination; receiving a plurality of location updates from the asset tracking device; determining whether the plurality of location updates are within a threshold distance of the route; and determining the asset tracking device is co-located with the carrier when one or more of the plurality of location updates are within the threshold distance of the route; determining (330; 430) a low power duration; and causing (340; 440) the asset tracking device to enter a low power mode for the low power duration; and detecting (310; 410) a trigger to perform a co-location check; in response to the trigger, determining (320; 420) the asset tracking device is co-located with a carrier en route to a destination by: determining a route of the carrier from an origin of the carrier to the destination; receiving a plurality of location updates from the asset tracking device; determining whether the plurality of location updates are within a threshold distance of the route; and determining the asset tracking device is co-located with the carrier when one or more of the plurality of location updates are within the threshold distance of the route; determining a route of the carrier from an origin of the carrier to the destination; receiving a plurality of location updates from the asset tracking device; determining whether the plurality of location updates are within a threshold distance of the route; and determining the asset tracking device is co-located with the carrier when one or more of the plurality of location updates are within the threshold distance of the route; determining (330; 430) a low power duration; and causing (340; 440) the asset tracking device to enter a low power mode for the low power duration; and the asset tracking device performing the steps of: transmitting the plurality of location updates to the asset tracking system; receiving a message from the asset tracking system, the message comprising a low power instruction and the low power duration; entering the low power mode in response to the low power instruction; and exiting the low power mode in response to expiration of the low power duration and exiting the low power mode in response to detection of an interrupt. transmitting the plurality of location updates to the asset tracking system; receiving a message from the asset tracking system, the message comprising a low power instruction and the low power duration; entering the low power mode in response to the low power instruction; and exiting the low power mode in response to expiration of the low power duration and exiting the low power mode in response to detection of an interrupt.