Ballistic damage to road signs and a comparison of shotgun test-firing methods

The current project was split into two separate parts. The first part recorded the number of road signs that had been damaged by gunshots in randomly selected rural locations across North Central Victoria, Australia, in an attempt to identify what variables could be used to determine where ballistic damage to road signs is most likely to occur. Using sign specific variables and location variables, a Generalised Linear Mixed-Effects Regression (glmer) analysis was conducted, which determined eight variables that were able to significantly predict sign damage. Rural locations in North Central Victoria, Australia that are most likely to have gunshot signs are locations with a low median age and a low median weekly income. Signs that are situated on straight sealed roads and are classified as regulatory signs are more likely to exhibit gunshot damage than some other sign types also situated on different types of roads. The variables shown to be significant in the current project may assist road maintenance agencies such as VicRoads, to identify the troublesome locations where sign damage is prominent and implement strategies to prevent damage from occurring.
The second part of the project compared two methods of measuring shotgun pellet spread, the Circle Overlay (CO) method and the Equivalent Circle Diameter (ECD) method. The methods were compared by measuring the spread of two types of shotgun cartridges, a 12GA Winchester Club 28g 7 ½ shot and a 12GA Winchester 36g BB-shot. Methods of pellet spread determination are used by law enforcement agencies such as Victoria Police, to estimate the muzzle-to-target distance at scenes where a shotgun has been discharged. The CO method was more consistent for the smaller 7 ½ shot, while the ECD method was more reliable at measuring the larger BB shot. This can assist Victoria Police and improve current procedures of pellet spread measurement and subsequent shooting distance determination.