Side brooms brush material inwards in front of the sweeping head. Vacuum, created inside the hopper by a large fan, pulls the material from the pickup head up into the hopper where large debris falls to the bottom. The air is then drawn through a large folded screen that causes any remaining dust and light debris to fall to the bottom of the hopper as well. The clean air then enters the fan inlet and is forced out to the pickup head, creating an “air knife” effect across the entire sweeping head. This scrapes the roadway surface with a sheet of pressurized air, lifting dirt and debris off the pavement.