Evacuation Report Card for U.S. Cities

The American Highway Users Alliance just published an interesting study of the evacuation capacity of highway systems in 37 major U.S. urban areas - those with populations of 1 million or more.

The cities' highway systems were graded in three dimensions:

• Exit Capacity: Capacity of major roadways leading out of an urban area.
• Internal Traffic Flow: Traffic flow within the urban area, allowing access to exit roadways.
• Automobile Access: The percentage of city residents with access to an automobile

Highlights of the study included:

• Half of the 37 cities received an "F." (New Orleans got a "D.")
• Only one city, Kansas City, received an "A."
• Landlocked cities scored the best, because evacuation is possible in any direction. Every city that scored "C" or above is landlocked.
• The three largest cities in the U.S. had the lowest scores: New York, Chicago, and Los Angeles.

Specific problem areas are:

• The majority of cities lack sufficient exit capacity, with New York and Chicago having the most severe problems.
• Los Angeles and Chicago have especially bad internal traffic flow.
• New York scores lowest by far on automobile access, because many city residents rely on public transit.

It seems to me that disaster planners in smaller cities could do this kind of analysis, too. While it does not take into account any obstacles that are caused by the disaster itself (e.g., bridges washed out in a hurricane or destroyed in an earthquake), it provides a good baseline snapshot of a city's ability to clear itself out.