Abstract: There is disclosed a highway tunnel surface cleaning vehicle having an adjustable boom at generally the center of the vehicle that extends over the cab and which carries a brush assembly made up of an array of linearly aligned brush units, the units rotationally supporting a number of driven brushes being articulated into a number of different positions by separate power devices to allow positioning of the brush units, and particularly their brushes, to accommodate the changing conditions of the surface to be cleaned. Also disclosed is a support structure for the brushes that allow selected brushes to be held out of operation, and a construction that allows the brushes to be flexibly supported and the cleaning liquid to be applied in close proximity to the brushing zone and prevented from escaping from the zone.