Abstract: An air resistance reducing assembly for use in tandemly coupled vehicles, one of the vehicles being a hauling, another of the vehicles being a trailing vehicle, the trailing vehicle including a front wall and a top panel, an the air deflector having leading and trailing edges disposed transversely of the direction of forward movement of the vehicles and carried at an upper leading end portion of the trailing vehicle, the deflector overlying the surface of upper leading end portion while remaining disposed respectively behind and below the plane of the front wall and the top panel, the air deflector being formed and disposed to deflect air to pass therebeneath adjacent the surface of the upper leading end portion and along the top of the trailing vehicle.