A wheeled vehicle, preferably a trailer, carries highway markers in a storage frame that is horizontally rotated to selectively align each of a plurality of parallel, circularly spaced, slide bearings, each configured to confine a linear array of highway markers against circumferential and radial movement, while allowing sliding along the length of the array. A powered abutment feeds the highway markers to a transfer station. A transfer mechanism picks up a highway marker by attraction and moves it between the transfer station and a highway station. A video camera records the highway station environment and wirelessly sends a video stream to a monitor plugged in the driver's cab. A releasable electrical connector between a tow vehicle and a trailer wheeled vehicle transmits a lights-on signal to control the operations. Power for the attraction, the transfer mechanism, the powered abutment, the camera, the retrieval attachment and a powered index mechanism for the storage frame are provided from a power supply on the trailer.