BackgroundVehicle-borne devices (VBDs) are a favored method. Davis  calls them “stealth of surprising power and efficiency” – the “poor man’s air force” – and notes that over a period of 20 years, VBD attacks have occurred in at least 59 countries. But, decision-making regarding blast protection for buildings is often undertaken using highly judgment-based risk processes. First, a design threat (that is, size of device) is specified, and a portfolio of mitigation measures is selected. The damages with the mitigation are then valued and, if deemed to be reasonable, the cost is looked at. If either the damages or the mitigation cost are thought to be unreasonable, the portfolio of mitigation measures is changed. As such, the probability tends to be treated as binary, 0 or 1, with the benefits and costs of the mitigation examined somewhat separately of one another [2,3,4,5,6,7,8,9,10]. The need for more risk-informed analysis for blast protection – including greater consideration of uncertainties – has been widely recognized [6,9,11,12,13,14,15,16,17,18].
AbstractDecision-making regarding implementing measures to protect buildings from vehicles is often done using highly judgment-based risk analysis. This paper gives a quantitative risk-cost model for using barriers to create setback distance around a new office building. The model explicitly analyzes both the attack probability, and the damages in the event of an attack (both target building and collateral), as well as how both of these might change as mitigation strategies are implemented. The damages are assessed using a new empirical model, which adapts the estimation methods used by the U.S. Geological Survey for earthquakes, and is based on data from three well-studied attacks. Monte Carlo simulation is used to carry the uncertainty in the inputs through to the final results. The model outputs are the mitigation costs, the attack damages, the “break even” attack probability (at which the value of the mitigation justifies its costs), and the cost per statistical life saved (assuming an attack). The results suggest that this mitigation option is economical only when the attack possibility (for the case without the measures present) is high.