The decals are made to strongly adhere to the surface of your vehicle and should not detach if properly affixed. However, if your decal does begin to detach from your window, bring your vehicle to Police Headquarters to have it removed. We will then exchange it for a new one. Again, it will be replaced free of charge only if the old decal is returned. (If you make sure that the surface of your vehicle is clean and dry before attaching the decal, it is highly unlikely it will fall off). Do not remove the decal from your vehicle and transfer it to any other vehicle at any time.