The causes for 131 fatal crashes of lap-shoulder belted occupants were analyzed for crash causation and avoidance opportunities. Fourteen crash scenarios were determined to depict the situation and circumstance of the accidents. Each scenario is discussed in relation to driver age, actions, behavior, errors and aggressiveness, as well as crash type and other factors influencing the crash.Nearly a third of crashes involved a rapid, unpredictable onset by reckless action or mistake of another driver. The remainder were caused by the driver of the case-vehicle. Some were single vehicle crashes primarily related to excessive speed, aggressive driving, and drifting out of lane. The others were multi-vehicle crashes due primarily to inadvertent errors. The most common errors were right-of-way violations at an intersection, loss of control on wet roads, impact of a stationary vehicle, and lane changing errors. Based on the scenarios, concepts for crash avoidance are discussed in relation to opportunities for improvements in vehicle safety.