One-page brief on resilient transportation networks

Critical Infrastructure: Resilient Transportation Networks

Facilities and services can be lost due to natural disasters or intentional strikes, either by terrorism or an army. An intentional strike against a communication or delivery system is called interdiction. The logistical effectiveness of civilian transportation systems may be substantially impacted by interdiction, and understanding the implications is essential to security planning.

Some infrastructure elements are more critical than others. For example, one link of a transmission system may be a key in providing power to an area, and alternate routes may not have the capacity to replace it. The loss of that link could be devastating.

Our focus is on developing decision support systems to identify critical infrastructure, to identify bottlenecks, to calculate the impact of the loss of specific system components, and to help design a plan of mitigation in the event of a loss.

An Example

Figure 1.  Five operating facilities. Weighted distance: 2950.

The most critical facilities are those which, when removed, produce the greatest impact on system operations. For example consider Figure 1, depicting a system of 5 facilities providing services to a region of demand.

The efficiency of this system  is measured in terms of weighted distance (e.g. trips x miles) of travel. Each demand is assigned to the nearest of the 5 facilities and the assignment is marked by a connecting line. The pattern depicted here is the optimal configuration. If 2 facilities were compromised, the worst case scenario produces the configuration given in Figure 2,  with a weighted distance more than 100% greater.

Figure 2.  Three operating facilities.  Weighted distance: 6124.
This means that “interdiction” could lead to substantial loss of efficiency if not the entire service. The results of this type of study can be used to identify the facilities that play the key role in service delivery. The value of this approach is (1) to identify locations where added security is warranted, (2) to develop mitigation plans should such facilities be lost, and (3) to redesign service systems that are less vulnerable.

The Solution

Researchers are developing analysis tools that can be used to model possible impacts due to interdiction and natural disasters.  The objectives of this research are:


Richard Church,
Paola Scaparra,
University of California, Santa Barbara