Hello, this is daft but im puzzled. Theres loads of work going on outside on the roads and theres a few vans with like a spinning thing on top, what is this? what does it do?
I always thought they were called hazard warning lights. There is a central bulb and a concave mirror spins around it directing the beam around 360 degrees. A yellow plastic or glass covering gives the light its characteristic colour.
If the unit is spinning it means that the van is in assist mode, that is when the driver, or front seat passenger, are assisting the propulsion of the vehicle by peddling.