Depending upon the location and hardness of the bushings, urethane bushings can cause a harsh ride and road noise in the vehicle. Depending upon where the urethane bushings are placed they can also cause handling problems in some suspensions. A suspension does not have to have anti-roll bars, however they are quite common on many vehicles. The anti-roll bar is designed to help reduce body roll or lean. By using anti-roll bars, vehicle manufacturers are able to reduce spring stiffness.
Softer springs improve ride quality and they help adhesion in many situations.
Anti-roll bars can also be used to improve handling balance. This is especially true on snow and ice. They can also be a disadvantage for serious off-road driving. When the load is reduced the spring decompresses, or releases its stored energy, and returns to its normal position or height. Rubber air bags are also a form of springs.