Automotive manufacturers are requiring lightweight materials, including glazing materials to improve vehicle fuel economy and meet government mandates. Taken as a group, the area of four side windows is comparable to that of a windshield, and, therefore, can offer significant weight reduction opportunities. As glass thickness is reduced, the acoustic and stiffness properties of the glazing change. Newer advanced interlayer materials have demonstrated the capability for overcoming the reduction in performance to maintain the properties of the original heavier constructions. One important design consideration for the side window position is reducing movement from impact of the door as it is closed at high velocities. The rigidity of lightweight glazing decreases with the decrease in glass thickness. Advanced interlayer materials offer enhanced rigidity over current constructions that improves performance by reducing movement when the door impacts the body when it closes at high velocities. In addition to loads applied quickly to a side window, the load in certain circumstances is applied more slowly. For instance, when a window is rolled down at highway speeds, the wind load causes deflection forces in the glazing. When designing for lightweighting, the functionality of the movable glass under these loads is critical, and will also be discussed. Additionally, as a glazing construction becomes thinner, more exterior sound is transferred through the construction. This effect can be managed with advanced interlayer materials that offer improved acoustic performance at higher frequency ranges. Design considerations for the reduction in glass thickness will be discussed and optimal construction options presented.