This document discusses road-vehicle performance and its impact on highway engineering and design. It covers the following key points: - Vehicle capabilities like acceleration/braking and human factors like reaction time form the basis of roadway design guidelines. - Tractive effort and resistance are opposing forces that determine vehicle performance. The three major sources of resistance are aerodynamic, rolling, and grade. - Aerodynamic resistance increases with speed squared and power required increases with speed cubed. Rolling resistance depends on factors like tire and surface properties. Grade resistance depends on road slope. - Maximum tractive effort is limited by the coefficient of road adhesion and weight transfer during acceleration or braking. Braking performance is important