Abstract: A vehicle suspension system with a control valve mechanism for regulating the air pressure within the vehicle's air springs that functions to increase the spring rate when the air spring is being compressed on curves and bumpy road surfaces. The vehicle suspension system would have an axle, a vehicle chassis, an air spring attached between the axle and the chassis, an air reservoir, and a control valve in an air line connecting the air spring and the air reservoir. The control valve has a housing with an air inlet port located in its top wall and an air exit port located in its bottom wall. A cylindrical plug member is mounted within the valve housing and it has a bore hole passing substantially diametrically through it so that when the position of the cylindrical plug within the housing is moved or adjusted the opposite ends of the bore hole can be aligned with both the air intake port and the air exhaust port at the same time.