Using roads for effective evacuation
Evacuation is seen as an appropriate way to reduce loss of life and other impacts. Evacuation, however, would cause significant disruption to both business and family life, and would also require significant resources. Against this, are the consequences in delaying the evacuation, which could mean that it is then not possible to evacuate everyone and evacuation is more chaotic and unsafe.
These issues highlight the need to understand better the logistical effort required to evacuate the public and in particular, how well the road network will perform. With this aim, the Government Office of the East Midlands appointed HR Wallingford to investigate the effective use of roads for evacuation in Lincolnshire and Norfolk.
A tiered approach to the traffic modelling was adopted. A “macro” (large) scale model provided a representation of demand over the modelled time period providing the peak traffic hour and total time required for evacuation. It provided a first assessment and identification of possible congestion ‘hot-spots’ over the whole area. The “meso” (medium) scale model provided information on localised traffic problems and congestion points.
Two scenarios were modelled. The ‘most likely’ scenario described the situation where the evacuating population use the roads best known to them. This scenario was then ‘optimised’ by modelling the situation where alternative routes are used by managing and directing the evacuating population to take more efficient routes, which reduce congestion and improve the required evacuation time. The results from these traffic models are being used by emergency planners in the development of evacuation plans.
Since completion of this study we have been appointed to repeat the assessment for the Humberside Resilience Forum. This second study includes application of the Life Safety Model to investigate traffic build-up on the local road network.
The results from these traffic models are being used by emergency planners in the development of evacuation plans.