Figure 5-2. Distribution of Causes and First Harmful Events

Figure 5-2 is a bar chart comparing first harmful events (y axis) with causes (x axis). The y axis shows values from 0 to 50 percent in 5 percent increments. The x axis shows seven causes: "HM Vehicle Driver Inattentive/Incapacitated," "Error in Judgment - HM Vehicle Driver," "Error in Judgment - Other Driver," "Mechanical Failure - HM Vehicle," "Mechanical Failure - Other Vehicle," "Vehicle Dynamics - HM Vehicle," and "Unknown." Approximately 28 percent of first harmful events are attributed to HM vehicle driver inattention; approximately 44 percent to HM vehicle driver error; approximately 24 percent to other driver error; and 3 percent or less to mechanical failure, vehicle dynamics, or unknown causes.