Abstract: An elevatable multi-function signboard system for highway vehicles, such as pavement/roadway sweepers, carries a warning/signal system that can be moved between a lowered position and an elevated position. In the lowered position, the signboard also functions to cover and protect auxiliary equipment mounted at the rear of the vehicle. The signboard is mounted to the vehicle by a multiple bar linkage and raised and lowered by a hydraulic cylinder arrangement under the control of the vehicle operator. The multiple bar linkage allows the signboard to swing-out rearwardly of the vehicle as the signboard is raised to effectively uncover any auxiliary equipment carried on the sweeper.