![What is this black Spinning thing on top of big black van? Ot speeds up and slows down, relative to the vehicle speed. I though maybe self driving radar, but maybe just What is this black Spinning thing on top of big black van? Ot speeds up and slows down, relative to the vehicle speed. I though maybe self driving radar, but maybe just](https://preview.redd.it/wfc65xdyhct11.jpg?auto=webp&s=ba2274a8615ef132c47c1550bf613621a8bee182)
What is this black Spinning thing on top of big black van? Ot speeds up and slows down, relative to the vehicle speed. I though maybe self driving radar, but maybe just
![What is this round spinning thing on the back of a utility truck? It only spun when the van was moving. : r/whatisthisthing What is this round spinning thing on the back of a utility truck? It only spun when the van was moving. : r/whatisthisthing](https://preview.redd.it/px9ajr2h56b11.jpg?auto=webp&s=21022dc84fc649b5e700df7aa9bbc909ce16e902)
What is this round spinning thing on the back of a utility truck? It only spun when the van was moving. : r/whatisthisthing
![Amazon.com: Cargo Bar Adjustable 40"-70", Small Rapid Ratchet Strong Steel Load Lock Rod for Pickups, Vans, & SUVs : Automotive Amazon.com: Cargo Bar Adjustable 40"-70", Small Rapid Ratchet Strong Steel Load Lock Rod for Pickups, Vans, & SUVs : Automotive](https://m.media-amazon.com/images/I/61VBk4pYqlS.jpg)