Bumps & barricades are most often used to limit or restrict the access of unauthorized personnel or vehicles to restricted or dangerous areas, for example construction sites, warehouses with hazardous materials, or production plants. These barricades prevent physical entrance to a restricted area to some extent, however they can be omitted with relative ease. The main function of these appliances is to indicate the restricted area and alert people about it. Traffic barriers are more suited for actual prevention. Besides indicating the prohibited area, some barriers are specifically designed to protect pedestrians from a vehicle moving at a high speed, or to prevent the vehicle from driving off the road, therefore they are hard enough to stop a car on impact, or at least slow it down considerably. Road bumps are designed to decrease the speed of a car, alerting the driver of a dangerous area.