In 2004, 182,243 traffic crashes occurred in Missouri, with 0.5 percent involving 1 or more persons being killed in the crash and 25.2 percent involving 1 or more persons being injured without fatalities. One person was killed in a crash every 7.8 hours. The data presented identify causal factors or characteristics of crashes that directly impacted the frequency of crash occurrence or death and injury-severity levels. Speed was a factor directly related to death and injury severity, along with drinking involvement, drivers under the age of 21, drivers 55 years old and older, the significant involvement of commercial motor vehicles, and failure to wear seat belts. Separate data are presented for crashes that involved motorcycles, school buses, bicycles, and pedestrians. An analysis of the features of crashes notes that motor vehicles striking fixed objects accounted for a large number of traffic crashes, especially those that resulted in death or injury. In fatal crashes, 41.8 percent involved a fixed object. Although hazardous materials were not involved in a large number of traffic crashes, they are a significant problem because of their potential for causing death, personal injury, and property damage through the release of such materials into the surrounding environment of the crash. Of all fatal traffic crashes, 0.2 percent involved hazardous materials. Construction/other work zones were not involved in a large number of traffic crashes; 1.9 percent of the traffic crashes involved a construction/other work zone, with 2.2 percent of fatal crashes associated with such zones. Extensive figures and tables