Abstract: This disclosure describes systems, methods, and apparatuses for providing visual and audio warnings to a vehicle driver warning of cargo on the vehicle roof when the vehicle approaches a structure. A low-power wireless transmitter can be coupled to each cargo item and is small enough to be left on the cargo when the cargo is used such that the wireless transmitter need not be removed from and reattached to the cargo. The wireless transmitter emits a wireless signal that a visual warning device coupled to the structure detects along with detection of a wireless signal from an audio warning device mounted within the vehicle. When both signals are detected, the visual warning device can provide a visual warning to the driver and also instruct the audio warning device inside the vehicle to audibly warn the driver.