Simulation of dependencies between armed response vehicles and CPTED measures in counter-terrorism resource allocation

Abstract

National and local governments must continuously adapt counter-terrorism strategies to new and evolving threats. With limited budgets, security architects and planners across the world face the same recurrent challenge: specifying a portfolio of effective measures and detailing where and when to deploy those. To perform this difficult task, methods have been proposed that apply a risk-based approach to solve this class of optimisation problems. However, many of those methods either ignore important aspects of the attacker-defender interaction or are too complicated to appeal to practitioners. Aimed at security specialists, this article uses simulation experiments to examine current responses to an unsophisticated but increasingly frequent manifestation of terrorism: vehicle and knife attacks. In particular, it shows that the optimal configuration of Armed Response Vehicles (ARVs) and measures of Crime Prevention through Environmental Design (CPTED) depends on whether offenders conduct hostile reconnaissance, the way they react to 2 the presence of security measures, and what attributes of the opportunity structure influence their actions most. Through this study, we demonstrate how information about offender displacement can be used to improve security strategies. We found that security architects and planners should not necessarily prioritise the most crowded and high-profile targets but could also consider deploying CPTED measures to protect nearby secondary targets. As we review the information underpinning our decision-making model, practical challenges in modelling displacement are then highlighted. Finally, a more general observation is made that, despite strong conceptual differences, ARVs and CPTED measures are, in fact, interdependent