Safety Analyzer
Integrating Risk Assessment and Routing for Effective Emergency Management
The network analysis and Multi-Criteria Decision Analysis (MCDA) are tools that can help municipalities in planning for emergencies. In the event of an emergency such as flooding or a chemical spill, quick and effective emergency management is critical for resource allocation and for providing directions to the citizens of the municipality. THe "At risk areas" MCDA displays on a map areas which are most vulnerable to hazards such as traffic accidents or flooding. The Network Analysis using a closest facilty and service area analysis find the fastest and closest drivetimes from a location to a temporary evacuation center.
MCDA
The overall MCDA workflow consists of assigning weights to the selected criteria using an Analytical Hierarchical Process (AHP). This allows the Weighted Overlay tool to run to complete the MCDA. Five criteria were evaluated and selected based on the idea that they would have a high impact on presenting a risk or hazard:
Criteria
Criteria Categorization
The Criteria as listed above are organized into a Analytical Hierarchal Process (AHP) rating Schema from 1-9, where 1 is the lowest suitability or highest risk and 9 is the highest suitability or least risk.
AHP Weight Assignment
Utilizing a specialized website tool intended for AHP tasks, an AHP Pairwise Comparison Process was conducted to assign weights to each criteria. The weights are determined by comparing each criterion with each of the other criterion individually.
Weighted Overlay Tool
After completing the AHP Pairwise Comparison Process and the Weighting Schema, the Weighted Overlay tool is run using reclassified surface criteria with their assigned weights to produce a final suitability surface combining every criteria.
Limitations/Improvements
An area of improvement for this MCDA is to add more sources of data. In this MCDA, a limitation is the lack of public data available to access to serve as the criteria. The theme of this MCDA is general hazards in the municipality, but there are only five criteria which do not cover every risk occurrence. For example, this MCDA does not have a criteria such as distance from a forest which could represent a hazard such as forest fires.
Network Anaysis
Data preparation
The network analysis workflow primarily consists of creating and configuring a road layer as a network dataset and then running the Network Analysis tool in ArcGIS Pro. The Network Analysis tool contains the service area and closest facility analysis which are used create the outputs. Preliminary data preparation involved linear referencing the chosen road layer as well as the other points involved in the network analysis, called incidents and facilities. Three new fields were added to the road layer called speed limit, distance and drivetime. The field drivetime is used as the Impedance or cost of the network analysis.
Drivetime(min) = (distance*60)/(speed limit)
Network dataset creation
The Network Analysis tool in ArcGIS Pro requires a network data source which can be provided by ArcGIS Online using credits or an alternative source can be built and provided by the user. This analysis uses a network data source that is built. Road topology was edited for topological errors that could cause issues with routing. The network dataset was created in a feature dataset and configured according to the requirements of the analysis by setting up network sources and travel attributes.
Service Area and Closest Facility
After configuring the network dataset and setting it as the source, the service area and closest facility analysis are run. Both analysis require the import of facilities and incidents. The service area analysis required the import of facilities (community service facilities). The closest facility analysis required the import of facilities (community service facilities) and incidents (businesses or civic addresses).
Limitations/Improvements
One area the closest facility could improve on is to incorporate barriers to close off areas to simulate a hazard or danger in an emergency. An example would be closing off several roads due to flooding. The current analysis assumes all roads are open with no road closures. The routing analysis included in the network analysis tool allows for the creation or import of barriers which will cause the created route to use a different road if it is blocked off.