According to traffic control manuals, which incidents typically cause highway closures for more than 2 hours?

Highway closures that extend for more than 2 hours are typically associated with major traffic incidents. These incidents can involve severe crashes, hazardous material spills, or significant vehicle fires that not only obstruct the roadway but also necessitate extensive clean-up and investigation processes. The complexity and severity of major incidents often require emergency personnel to secure the area, assess risks, and carry out necessary interventions, leading to prolonged disruptions.

In contrast, minor traffic incidents usually result in shorter closures, as they often involve minimal damage and require less time to clear the roadway. Intermediate incidents may cause moderate delays but generally do not escalate to the severity that would warrant extended highway closures. Routine traffic conditions, on the other hand, do not lead to any closures, as they typically reflect normal traffic flow without significant disturbances. Thus, it is the nature and extent of major traffic incidents that directly correlate with lengthy highway closures.