A system for draining non-gaseous fluid wastes from road vehicles having a width substantially not exceeding a predetermined maximum width(Lmax), the system comprising: a) a transit surface on which road vehicles can pass and stop; b) a collecting tank located on the transit surface and comprising in turn a substantially concave collection area capable of collecting and containing the non-gaseous liquid and/or fluid wastes drained from a road vehicle positioned above the same collection area, wherein - the collection area having such a size that it extends over at least half the predetermined maximum width (Lmax); - the collection area of the collecting tank is located on the transit surface so that a vehicle can transit above the collecting tank 1) with at least one wheel thereof resting directly upon said collection area, - said concave collection area has an elongated shape with substantially V-shaped or U-shaped cross sections, having a maximum depth (Pmax) not exceeding the predetermined maximum width (Lmax) of the transversal cross section of the collection area in correspondence with maximum depth (Pmax); c) a proportioning pump with a disinfectant reservoir and two pipes in the upper portion of the long sides of the collection area having a set of several micro-holes, for injecting a water/disinfectant mixture into said collection area of said collecting tank; characterized by two photoelectric cells detecting the presence of the road vehicle, being and a pedal pushbutton for wash activation, the collection area being arranged transverse to the transit surface, so that the bottom of the collection area has an increasing depth from one end to the other one of the collection area and a well is provided at said other end of the collection area. a) a transit surface on which road vehicles can pass and stop; b) a collecting tank located on the transit surface and comprising in turn a substantially concave collection area capable of collecting and containing the non-gaseous liquid and/or fluid wastes drained from a road vehicle positioned above the same collection area, wherein - the collection area having such a size that it extends over at least half the predetermined maximum width (Lmax); - the collection area of the collecting tank is located on the transit surface so that a vehicle can transit above the collecting tank 1) with at least one wheel thereof resting directly upon said collection area, - said concave collection area has an elongated shape with substantially V-shaped or U-shaped cross sections, having a maximum depth (Pmax) not exceeding the predetermined maximum width (Lmax) of the transversal cross section of the collection area in correspondence with maximum depth (Pmax); - the collection area having such a size that it extends over at least half the predetermined maximum width (Lmax); - the collection area of the collecting tank is located on the transit surface so that a vehicle can transit above the collecting tank 1) with at least one wheel thereof resting directly upon said collection area, - said concave collection area has an elongated shape with substantially V-shaped or U-shaped cross sections, having a maximum depth (Pmax) not exceeding the predetermined maximum width (Lmax) of the transversal cross section of the collection area in correspondence with maximum depth (Pmax); c) a proportioning pump with a disinfectant reservoir and two pipes in the upper portion of the long sides of the collection area having a set of several micro-holes, for injecting a water/disinfectant mixture into said collection area of said collecting tank;