A liquid fuel tank that, (a) if mounted on a trailer, extends outboard of the vehicle frame and outside of the plan view outline of the cab; or (b), if mounted on a motor home, extends outboard of a line parallel to the longitudinal centerline of the motor home and tangent to the outboard side of a front tyre in a straight-ahead position. In determining whether a fuel tank on a trailer or motor home is side-mounted, the fill pipe is not considered a part of the tank.