Lightbars are the maximum amount of 360 degree warning lighting. These get mounted to the top of the vehicle and usually contain a variety of other features.
The lightbar gets mounted mount to the roof of the vehicle. A proper installation requires holes to be drilled through the roof of the vehicle in order to route the wires. Although not recommended, if your car is a lease drilling may be avoided. If a hole drilled is then sealed and weatherproofed properly.