<div class="htmlview paragraph">An urban area is an excellent laboratory to conduct vehicle accident investigations. The central city of Los Angeles, California and the entire city of Miami, Florida, will be the geographical areas discussed. These areas experience a large number of accidents in a relatively small geographical region and contain diverse numbers and types of vehicles, collision configurations, and accident severity levels, <span class="xref">Figure 1</span>. Within the designated urban area, the Accident Investigation (AI) team maintains close cooperation with all law enforcement agencies, along with many other federal, state and local agencies.</div>