Aspects of the disclosure are directed to characterizing effective vehicle frontal area. As may be implemented in accordance with one or more embodiments, one or more operating parameters of the vehicle are obtained. Such parameters may be obtained during one or more qualifying periods of time, such as those periods in which an operating parameter or parameters such as speed and/or acceleration are within a range of values. A value that provides an estimate of the vehicle frontal area is then generated based on the one or more operating parameters.