Guideline - Department of Housing and Public Works - Queensland ...

Step 7: Route capacity
Determine the capacity of, and travel time along, the evacuation routes.
The capacity (people/hr) of the evacuation routes will vary depending upon route conditions. A range of route
conditions, normal and disrupted and, if appropriate, enhanced and blocked should be examined.
Where the time necessary for evacuating the community is greater than six hours, for the normal route condition,
determine the appropriate level of emergency management intervention to achieve an evacuation within
six hours. Determine the enhanced capacity of the evacuation routes.
Identify hazards which may block the evacuation route. Determine an alternate means and the rate of evacuation.
Route capacity should be assessed individually for each community. The capacity is often controlled by the capacity
of the intersection.
Step 8: Route vulnerability
Quantify the vulnerability to hazards which may block the evacuation route.
The route vulnerability can be quantified in terms of the likelihood of occurrence, for example, a road flooded at a
creek by a Q20 flood.
Route conditions
‘Normal’ - Fine weather with normal traffic control.
‘Enhanced’ - Emergency agencies intervene to increase the route capacity. Several options are available. These
include: ensuring a minimum number of people per vehicle; banning vehicles towing caravans and trailers; traffic
control at intersections; both lanes in one direction.
‘Disrupted’ - Heavy rain with possible vehicle break-downs and traffic accidents. Other disruptions may occur
depending upon location. These include: traffic light failure; fallen trees; and localised land slips or flood water over
road but still trafficable with care. In this condition the route capacity is reduced and possibly blocked until emergency
personnel clear the obstruction. In this case the capacity may be described as people/hour plus a delay period in
hours to remove the hazard.
‘Blocked’ - Route is closed by flood waters or large scale land-slip and cannot be cleared in the evacuation period.
An alternate route or means of transport needs to be identified and the route capacity determined.
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Disaster Management Planning Guideline
Mitigating the Adverse Impacts of Cyclone – Evacuation and Shelter