Residential

A residential unit is an urban object, which is generally zoned or designated for dwelling purposes and designed to accommodate housing facilities in which people can live.

Description

Residential areas are typically classified as providing varying amounts of living accommodation for people. Residential areas are usually designated as such by the development plan of the authorities of a city or municipality, including the amount of units and, consequently, the approximate number of people living in that area following the prescribed density. The amount of land zoned for residential development should be in line with the projected population growth figures, as set out in regional strategic development documents (such as Regional Planning Guidelines).

Residential areas will generally consist of various accommodation types: apartment schemes (medium to high density), detached or semi detached houses (low to medium density), or terraced housing (medium to high density). The character of a residential area can be influenced heavily by the mixture of tenures (owner occupier, private rental, social housing) which are available within an area. All of these factors will have an influence on the security of a residential area.

Residential building types

Residential development can encompass a wide variety of structures. For simplicity and clarity, the broad spectrum of residential building types is divided into three archetypes:

Residence type	Description	Icon
Housing estates	Housing estates consist of detached, semi-detached and/or terraced housing, typically with some level of private open space associated with each unit.
Housing blocks	A housing block is made up of a rectangular layout consisting of connected residential units, often with a private open square contained within it.
High rise housing	High rise housing consists of apartment schemes usually in excess of 6 storey's in height, although apartment schemes of lower height are common.

These archetypes will never completely fit any specific situation, but are used to present the typical issues associated with these archetypical situations. Thereby enabling the reader to decide to what extent it applies to his or hers specific situation.

In the text below, any of these three icons will be used whenever a observation is specific to one or more of the above mentioned archetypes.

Functions

Social

From the security point of view, the prior social importance of residential areas is to provide a trusted environment for citizens that enhances communal resilience while reducing vulnerability. The importance of housing is recognised in the United Nations Covenant on Economic, Social and Cultural Rights, that includes 'the right of everyone to an adequate standard of living for himself and his family, including adequate ... housing'.

Resilience-enhancing aspects

Residential land use is very important to a citizen's quality of life, and the standard of housing experienced by citizens will have a significant impact on overall health. Housing provides shelter, fulfilling basic human needs, and privacy. The quality of housing is influenced by size, amenities, habitability, and general liveability. The attractiveness of residential areas and the wider urban environment are important from a societal security point of view since they have an impact on resilience, at individual and collective levels, as illustrated by the following examples:

• Residential areas should provide some aspect with which citizen's can identify (be it employment or a recreational facility) and offer the services or facilities that they seek. Some people, who rent property within areas, may feel less of a sense of ownership or commitment for that area if services or facilities are lacking.

• Communities with high levels of 'collective efficacy' – the capacity to produce an effect collecively - high levels of cohesion, and mutual trust will be willing to intervene to potential disruptive behaviour and stop it from escalating. Communities with low levels of ‘collective efficacy’ (e.g. areas with a high proportion of young offenders as a result of a churning migrant population with shifting moral values, high levels of poverty, and low levels of community cohesion) will be less willing or able to intervene.

Vulnerability-reducing aspects

What makes an area a good place to live?

There are a couple of relations between the built environment of a residential area and its vulnerability from a security point of view, such as the following:

• The level of safety and security is a very important value in the perceived attractiveness of a residential area (see illustration), as residential areas provide the home base for people and their families. In addition, inadequate housing increases the risk of ill-health and disability; it can also lead to poor mental health. Areas having inadequate housing usually coinside with lower educational attainment, unemployment, and poverty in that same area.

• Poor residential development (bad housing) can impact children's future chances. The Shelter housing agency report 'Chance of a Lifetime' documents the powerful influence of poor housing on children's lives and shows how its destabilising impact resonates well into adulthood. In every aspect of life - mental, physical, emotional, social and economic - living in bad housing can leave a devastating legacy on children. Studies show that poor housing can lead to a 25 per cent higher risk of experiencing severe ill-health and disability before they reach middle age. It can have a devastating impact on emotional wellbeing. Research also shows that bad housing can lead to behavioural problems and offences in juveniles:

How does bad housing affect children’s chances to make a positive contribution in life?

• Homeless children are more likely to show signs of behavioural problems such as aggression, hyperactivity, and impulsivity.
• Homeless children are three to four times more likely to have mental health problems than other children,;
• Poor housing conditions and overcrowding may also contribute to the emergence of problem behaviour;
• Behavioural difficulties in childhood, which may be attributable to or exacerbated by bad housing, can manifest themselves in offending behaviour later in life. In the UK, nearly half of male remand young offenders and 42 per cent of female sentenced young offenders have experienced homelessness)..

Hazard-reducing aspects

• Quality of residency also has criminological impact; it can contribute to preventing or creating hazard. Evidence suggests that nearly half of young offenders have experienced homelessness as a child, and the roots of offending behaviour may well be traceable to problems that emerge when children grow up in such conditions.

• Research has also shown that a wide range of features of the physical environment at the street block and neighborhood level have proven relevant to predict crime rates and crime-related outcomes, such as fear of crime and neighborhood confidence. These aspects among other things relate to the perception of hazard.

In terms of practical methods, crime prevention by design - for example "crime prevention through environmental design" (CPTED) - is of priority in this field, although it also involves some measures directed at vulnerability reduction rather than reduction of hazard.

Economic

Residential areas accommodate the people who operate in and utilise the economic systems of the urban area. Additionally, residential areas both enhance a communities’ ability to attract new business, and in the same time provide citizens with one of its most basic needs (housing). As a whole, residential land use is the most valuable urban spatial structure due to its great aggregate value and economic impact for the local economy. Moreover, residential areas foster critical population mass which contributes to economic, social and transport (infrastructure) activities. These economic impacts can be estimated with the help of economic tools/techniques.

The most common types of residential security threats (in terms of human intent) are crime related (e.g., domestic burglary, robbery, graffiti, assault, etc.). Crime generates costs in anticipation of crime (e.g. locks, surveillance, etc.), as a consequence of crime (loss of property) and in response to crime (police investigation, legal system, etc.). Indirectly, crime has (amongst others) an impact on, for example, the local real estate value.

Security devices such as locks, closed circuit television, surveillance or improved street lightning have an economic impact (of security measures) (in terms of costs and benefits) which can be considerable. Another way to enhance security is by design, e.g. the designing out approach, or as an aspect of sustainable design, which seeks a balanced consideration of social, economic, cultural and environmental aspects in urban design. In general, these measures demand larger investments than traditional security measures, but at the same time they are able to avoid future costs due to the long-term prevention of crime. An example of home security measures:

The Association of British Insurers (ABI) performed a cost-benefit analysis on target hardening measures for home security. The analysis was based on the estimates of the average household cost of burglary (£3,300), the average cost of Security By Design (SBD) target hardening (£630), burglary rates (average 2.7 - 6.7% range), and socio-economic demographics. The per household net present value benefit of target hardening measures was projected over 20 years, yielding benefits of over £1,170 per household. As a result, the average household benefits are nearly double the average cost of the introduced security measures.

Mobility

The presence of large numbers of people living within one part of an urban area brings with it a requirement for mobility, in allowing them to move throughout the urban area to take advantage of the various functions on offer within its different parts.

The transportation demand in a network depends on the functions of the different zones in a network. With demand estimation models, the demand can be estimated as the expected number of trips in a certain time period for a certain modality (e.g. car, public transport) between each combination of origin zone and destination zone, depending on the function of the zones. This is also called a trip market. For a residential zone, in the morning there will be many trips going out (e.g. towards work, school), while in the afternoon there will be large demands going into the zone. This should be taken into account for operating traffic management measures or for predicting future/expected traffic flows.

Furthermore, in order to prevent crime, the mobility network should be designed such that there are as little spaces as possible that cannot be seen easily by the public. Crime and anti-social behaviour are more likely to occur if criminals can operate, including travelling to and from the location, without fear of being detected; and if all sides of buildings and all parts of spaces are not overlooked by surrounding users or passers-by .

Cul-de-sacs

Residential areas can benefit from a design that minimises transit through the area, as crime is positively related to the amount of traffic through an area and residential areas only need good entry and exit points and can function perfectly well as cul-de-sacs. Homes in cul-de-sacs can be highly secure, but the cul-de-sac should be short and straight (to allow visibility from one end to the other) and should not be joined by networks of footpaths that are irregularly used but likely to foster criminal activity . It should be borne in mind however that while cul-de-sacs can be beneficial from a crime-reduction perspective, many urban planners and designers do not favour their use, as they can create an introverted layout which fails to integrate with the surroundings.

Safety

Safety, in all its forms, is an important function for the perceived quality of these environments. The common presence of children in residential areas further elevate the required safety standards. Although these environments are designed to provide safety, the safety function can be deteriorated by crime. Examples of crime deteriorating safety are:

• 

  Vandalised electricity meters, leading to potentially unsafe situations
  Vandalism: destruction of safety features (such as traffic signs, fencing around dangerous areas or child-safe playgrounds) can lead to dangerous situations and safety hazards.
• Burglary often leads to substantial damages due to the forced entry. Broken windows and doors no longer provide shelter for the cold, wind, rain, which can lead to subsequent safety hazards, such as with electricity and wet surfaces.
• Antisocial behaviour can for instance endanger people by generating street litter, such as broken bottles or reckless driving
• Drug offences can also lead to dangerous litter in the streets, such as used needles.

Security Issues

Crimes most relevant to residential areas, are:

• Burglary
• Vehicle theft
• Robbery
• Assault
• Sexual Assault
• Vandalism
• Graffiti

Of these crimes, burglary is generally regarded as the most relevant to residential areas. Burglary is a security issue that is, amongst others influences, affected by the population density. Alhough, a high population density is generally associated with high rates of assault and burglary, when corrected for the presence of poverty and lack of vegetation, rates of assaults and burglaries are higher in more sparsely populated neighbourhoods. This means that especially high-density neighbourhoods with little vegetation are prone to these issues. Many traditional designed high-rise residential environments were designed with these qualities, leading to relatively high levels of crime and a tendency for early deterioration.

Measures

• Directing traffic flows can be effective both in preventing criminals to become aware of opportunities and reducing the opportunities for approach of a target. Especially housing blocks and housing estates can benefit from a careful design of traffic flows, effectively reducing the 'visibility' of an area to criminals. For high-rise housing this is less effective due the high visibility of the structure.
• Target hardening can greatly increase the effort needed for criminals to enter the object and thereby reduce the attractiveness of a n object
• Surveillance can be effective against mentioned security issues, but can incur high costs if implemented as dedicated observers, either on location or remote. A more natural form of surveillance is surveillance by the inhabitants (also known as 'natural surveillance'). This can be very effective if the right conditions are met, such as adequate surveillability of the environment (from the own home), social cohesion and a sense of ownership. These factors can all be influenced by the structure of the built environment, but have proven to be most challenging to achieve in high-rise housing .
• Intervention force is needed to make detection measures, such as alarms or surveillance effective
• Target removal such as the removal of coin operated gas and electricity meters in houses or coin operated parking meters
• Facilitating compliance can prevent littering by providing ample waste bins, it can prevent unwanted traffic flows by careful design of the mobility in an area
• Ownership is an important aspect in the prevention of unauthorized entry by creating a clear distinction between public and private space
• Maintenance and designing for easy maintenance can be used as the removal of a crime motivator, as deterioration can be an incentive to crime
• Removal of crime motivators ensures the separation of perpetrators , their incentives and opportunities, Such as the prevention of blank, reachable and highly visible walls to prevent graffiti.

A combination of these measures is used in the practical approach 'secured by design'.