Measure: Intervention force

Establishing an intervention force is the measure of having adequate resources (first responders) to react to emergencies in order to minimise impact and restore a normal situation as soon as possible.

Description
An intervention force is the last link in the reaction chain detection-perception-interpretation-formulating action-acting of the comprehensive approach. The essence of deploying an intervention force lies in intervening in an observed incident. This is done by way of first responders, who by their action minimize impact, restore the situation to normalcy and in general also take actions to facilitate the prosecution, if needed.

Examples
Intervention forces can be officially appointed, ad-hoc, public or private. Examples of forms of intervention force are:
 * Police force
 * Army
 * Private security companies
 * Neighbourhood watches/other citizens initiatives

Effectiveness
The effectiveness of a intervention force against crime lies in three factors:
 * the mitigating effect of authority present
 * the direct actions undertaken by the intervention force to mitigate the effects of an incident
 * make contributions to the prosecution of crime (gathering evidence and leads and arresting suspects)

Security issues where this measure can be effective and influenced by the urban planner are :

General considerations

 * For a intervention force to be effective, they need to be well aware of the situation; what parties are involved, in what way, what are their motives, goals, backgrounds and means, what has happened and where are the parties located.
 * In order to get this awareness, it is essential that the reaction chain is unbroken. As often the links in the reaction chain are managed by different people or organisations, the communication in this chain is of vital essence.
 * A timely arrival at the location of the incident is essential to keep the number of options to resolve the situation as open as possible; an incident can escalate very quickly, making gentler interventions impractical or impossible.

The extent to which a intervention force can operate effectively in an urban context is dependent of:
 * The travel time to the incident. A short travel time from the place of deployment of the intervention force to the location of a (potential) incident. traffic management measures such as incident management and Evacuation management are vital for maintaining robustness in travel times to incidents.

Urban planning considerations
Urban planning processes should take into consideration measures to support the needs of intervention forces (such as first responders) in responding to developing emergencies and crisis situations in urban spaces. Cooperation and dialogue should be facilitated and supported between intervention forces and urban planners to identify problem areas in advance so that any challenges intervention forces may face in attempting to efficiently and effectively carry out their duties are mitigated. An example of which may be an instance where there are no easily accessible water supplies (such as fire hydrants) available for fire extinguishing, or where target hardening measures have inadvertently inconvenienced the police from intercepting and pursuing a criminal.

Safety/security considerations
The duration and impact of incidents can be minimized by applying proper incident management, which requires among others a good cooperation between the agencies responsible for incident management. Incident management is used to reduce the time to detect and verify an incident occurrence; implement the appropriate response; and safely clear the incident, while managing the affected flow until full capacity is restored.

The publicity resulting from a large-scale deployment of intervention force can deteriorate the status of a neighbourhood, which may attract more crime in the short term.

The use of violence in interventions can cause damage and injuries.

Intervention forces can be highly flexible and therefore also perform as a means to provide safety. For instance, security officers might be knowledgeable in providing first aid.

Social considerations
The deployment of intervention forces can lead to feelings of victimisation on the side of the affected public. Therefore, an important social aspect is the responsiveness of the measure to citizens' felt security needs. A measure, such as intervention force, will only be responsive if it is based on identification of citizens' self-perceptions of vulnerability and resilience as well as their relation to/interaction with resilience-enhancing measures centred on built infrastructure. This can best be accomplished by appropriately involving citizens, based on a set of introduced methods of citizen participation as compiled by VITRUV.

Economic considerations
The mitigating effect of intervention forces prevents material and immaterial costs for those who have become victimised, and on top of that prevents secondary economic damage to local and regional economies (in terms of e.g. a decrease in tourism or investments by companies). Intervention forces are a widely used measure to fight crime and terrorism, and in most cases the primary responsibility of public authorities. These benefits however, are not possible without cost: Being the first line of defence, public authorities annually spend billions on policing. Intervention forces are primarily characterised by the permanent investments in training, equipment and salaries of its team members. Hence, intervention forces require more long-term investments than, for example, target hardening measures (i.e. toughened glass or concrete walls) or remote surveillance with the help of cameras. There exist, nevertheless, relatively few rigorous studies by economists, political scientists, and criminal justice researchers on the impact of policing, and specifically the function as an intervention force (see the case example below).

Case example: The cost-effectiveness of policing "According to Levitt (2004), until the start of this decade, most studies found an insignificant or negative correlation between the number of police forces and criminal offences. According to Levitt, however, this is due to the fact that these studies failed to account for the fact that policing does not only influence crime, but also the amount of crime influences the amount of policing. Correcting for this effect, more recent studies conclude that more police is associated with reductions in crime, and Levitt (2004) concludes that, based on a crude approximation, the effectiveness of policing from a cost-benefit perspective is “attractive”, but should not be the sole focus to reduce crime."

The conclusion of Levitt (2004) in the case example above is that even though policing is an attractive measure from an economic point of view, it should not be the sole focus to reduce crime. This point illustrates very clearly that in order to make a well-considered decision about investment in intervention forces, one should not just limit the cost-benefit analysis to this specific type of measure, but also to other types of measures (including preventive security measures). Economic tools can help decision makers to reach this well-considered decision (of course in collaboration with insights from criminology, sociology, etc.).

Mobility considerations
The deployment of a intervention force is a relatively expensive measure, as it needs to be maintained at all times in order to be deployable when needed.

In the mobility field, many efforts have been put into the development of adequate incident management procedures; in case of incidents, the aim is to get as quickly as possible the required emergency services (incl. police) at the place of the incident and clearing the road as fast as possible, in order to minimize the mobility effect for the other traffic.

Generally, accessibility of risk sensitive locations should be guaranteed or made as good as possible in order to offer easy access for intervention forces in case of emergencies or other incidents.

Ethics considerations
This measure does not have immediate relations to planning for built infrastructure and its ethics aspects. However, build infrastructure may be designed with considerations in mind such as how accessible it will be for intervention forces. This relates to the more general aspect of environmental design.

Use of uniformed force and its legitimacy/acceptability can greatly vary across cultures and sub-cultures. To support this, VITRUV offers a commented list of methods to determine ethics aspects in relevant urban planning.

Legal considerations
Legal considerations when considering intervention force measures are:
 * Public participation - Depending on the way the forces are deployed, public participation could be positively or negatively influenced