Crime prevention through environmental design

The principles of Crime Prevention Through Environmental Design (CPTED) are based on the idea that the environment influences people's behaviour and good design minimises the potential for criminal behaviour to occur.

Living wall of plants on Victoria University building.
Green wall at Victoria University

The principles behind this design theory can be grouped into five areas:

Ideally, you should incorporate these principles at the design stage of a development, but you can apply them to existing buildings and areas.

Surveillance

Surveillance involves making a site visible, as casual surveillance increases a sense of safety and can deter criminal activity. You can usually achieve this by using sightlines and lighting, and getting more people to use an area.

Designing sightlines

You can use sightlines to help keep an area less susceptible to crime and graffiti. Maintain vegetation and landscaping so the area is visible:

  • keep shrubbery and trees lower than 60cm or have 1.8m between their lowest branches and the ground
  • minimise blind spots and sharp corners
  • position gathering spots in areas that offer natural surveillance and access control.

Appropriate lighting

Lighting in well-used areas may deter offenders by increasing the risk of them being caught:

  • lighting should be uniform and not create glare
  • height and location of lights are important
  • in isolated or remote locations, additional lighting may attract graffiti or crime as it lets the offender see their work
  • lighting that works on motion detectors may deter graffiti or crime in these locations.

Natural surveillance and formal observation

You should make areas that have a high risk of graffiti or crime more visible from public places such as roads, footpaths and neighbouring buildings, as this increases natural surveillance. Design landscaping to enhance sightlines, allowing users of a space to see what is happening around them.

Formal observation involves techniques such as putting a reception desk in a place that enables surveillance. Other examples include rostering staff to tend to an area at vulnerable times (such as after school), or asking neighbouring businesses or residents to call the Police if there is suspicious activity.

Access control

Control people’s access to locations prone to graffiti or crime by using, for example:

  • physical barriers
  • signs that indicate restricted access.

Access to areas

  • Make sure there are clear transitional zones from public to semi-public to private spaces, such as a change in level, a garden bed or different paving.
  • Use fences, rails and other barriers to discourage or deny access.
  • Limit access to roofs and higher stories by moving bins and other items away from walls and covering downpipes to stop people climbing them.

Access to canvases

If you can't alter graffiti ‘canvases’ (walls, doors etc) to reduce their attractiveness to graffiti vandals, you could use landscaping or planting to cover them. Make sure that any plants used do not damage the surface by attaching themselves to the wall or by root invasion.

  • Landscaping should be high enough to cover the accessible parts of the wall and wide enough to deter access.
  • Natives and other plants that are uncomfortable to be close to may help to keep people away.
  • Pebbles and other ground covers can be used in areas where making noise will alert a response. Take care to make sure these items can't be as projectiles.
  • Community art, especially mosaic tiles, may be useful when landscaping is not an appropriate solution. Mosaic tiles provide a bright and colourful surface, which is textured to prevent graffiti vandalism and is relatively easy to clean if it does occur.

Access to graffiti tools

Controlling access to materials used for graffiti (such as spray cans and marker pens) discourages and prevents graffiti.

  • For retailers, including hardware and discount stores, it is against the law to sell spray cans to people under 18 – and access to spray cans in-store must be restricted. The sale of marker pens should also be assessed. 
  • Securely store any spray cans on your property and dispose of them carefully.

Territoriality

Physical features and activities help to show ‘ownership’ and ‘control’ of the environment – this is called ‘territoriality’.

Safe and well-used spaces

The community will use areas that are well designed, safe and enjoyable – creating vibrant areas that are less susceptible to graffiti and crime.

  • Activities such as cafés, children’s play equipment and public art will encourage legitimate use.
  • You can use signs and clear pathways to remove excuses for being in restricted areas.

Increased reporting of graffiti vandalism

In well-used areas, suspicious behaviour (such as people accessing rooftops) will be obvious and more likely to be reported.

  • Reporting graffiti to the Council and your local police station helps to control the spread of graffiti, better planning of patrols and use of resources.
  • Reporting graffiti to property owners means they can remove it as soon as possible.

Graffiti-resistant materials

Using graffiti-resistant materials can help prevent graffiti and make it easy to clean up.

Materials

Use easy-to-clean construction and design materials in areas vulnerable to graffiti vandalism. Seal porous materials or apply an anti-graffiti coating. Options include:

  • vitreous-enamel panels or glazed ceramic tiles from which you can wash off the graffiti
  • wired glass that you can clean with scrapers
  • polyester film over glass
  • plastic laminates
  • signs with surfaces resistant to marker pens and spray paint.

Texture

Surface texture can reduce the attractiveness for graffiti offenders. By incorporating open form designs, you can reduce the size of the available ‘canvas’ and improve the visibility of the area. Examples include:

  • pool-style fencing, such steel mesh and latticework
  • irregular finishes such as roughly rendered brick (however, this surface can be more difficult to maintain).

Maintenance

Ongoing maintenance shows that an area is well used and cared for. This includes:

  • regular tree trimming
  • routinely checking locations prone to graffiti vandalism
  • removing graffiti as soon as possible.