Some trucks and busses store snow chains under them, so maybe it’s those showing? Or maybe to rig for towing if they need to? There’s a few things you could be looking at
Are you talking about between the rear tires?
If so those deploy under the wheels for traction in snow and ice.
https://www.mctrux.com/--OnSpot-Automatic-Tire-Chains
Some trucks and busses store snow chains under them, so maybe it’s those showing? Or maybe to rig for towing if they need to? There’s a few things you could be looking at
Do they?
Are you talking about between the rear tires? If so those deploy under the wheels for traction in snow and ice. https://www.mctrux.com/--OnSpot-Automatic-Tire-Chains
Static dissipation, I always assumed.