HGV (Heavy Goods Vehicle) sidebars, also known as side guards or side underrun protection, are safety features designed to protect vulnerable road users, such as pedestrians, cyclists, and motorcyclists, in the event of a collision with a large truck or lorry. They are mounted on the side of the vehicle, typically between the front and rear axles, to prevent a person from being dragged under the wheels of the truck if they are involved in an accident.