Our paper examines how street-level drug markets adapt to a macro-level
disruption to the supply of heroin, under three experimental conditions of street-level
drug law enforcement: random patrol, hot-spot policing and problem-orientated policing.
We utilize an agent-based model to explore the relative impact of abstractions of
these three law enforcement strategies after simulating an ‘external shock’ to the
supply of heroin to the street-level drug market.We use 3 years of data, which include
the period of the ‘heroin drought’ in Melbourne (Australia) that commenced in late
2000 and early 2001, to measure changes in a selected range of crime and harm
indicators under the three policing conditions. Our results show that macro-level
disruptions to drug supply have a limited impact on street-level market dynamics when
there is a ready replacement drug. By contrast, street-level police interventions are
shown to vary in their capacity to alter drug market dynamics. Importantly, our
laboratory abstraction of problem-orientated policing is shown to be the optimal
strategy to disrupt street-level injecting-drug markets, reduce crimes and minimize
harm, regardless of the type of drug being supplied to the market.