Crime Prevention Through Environmental Design, or CPTED, is the proper design and effective use of the built environment that can lead to the reduction in incidents and fear of crime and thereby improve the quality of life.
CPTED utilizes four strategies:
- Natural surveillance
- Access control
- Territorial reinforcement
- Maintenance
Natural Surveillance calls for the design, or layout, of the property to allow for visibility by legitimate users and to keep possible intruders under observation. An example is a windowed stairwell or a front office overlooking the parking lot of entrance area. Additionally, properly selected, installed, and maintained landscaping allows for unobstructed views of otherwise vulnerable doors and windows.
Territorial Reinforcement is marking territorial control of a 
space while discouraging potential offenders who perceive this control and avoid it.
Territorial reinforcement employs such design elements as sidewalks, landscaping, fences, and porches, to help distinguish between public and private areas and helps exhibit signs of "ownership" that sends a "hands off" message to would-be offenders. Bollards can be used to prevent vehicle traffic into pedestrian areas. Lighted bollards also assist with access control.
Natural Access Control employs elements like doors, shrubs, fences, and gates to deny admission to a crime target and to create a perception among offenders that there is a risk in selecting the target. The primary purpose of an access control strategy is to deny access to a crime target. Physical and mechanical means of access control include locks, bars, alarms, and fencing. Limit ingress and egress to the building or facility through one area. This area should also allow for Natural Surveillance.
Use signs to direct visitors to appropriate buildings, entrances, and parking. Pedestrian scale lighting should be utilized along outdoor walkways and sidewalks.
Maintenance, including cleaning, repairing, and landscaping, needs to be performed routinely to encourage use of the space for the intended purpose and discourage abnormal and criminal use. Maintenance sends a clear signal that someone cares about the space and is likely to defend against it intruders or vandals.
Keep all structures, including fencing and walkways, clean and in good repair. Keep all litter and trash picked up at all times. Keep trees and shrubs trimmed back from windows, doors, and walkways. Keep shrubs trimmed to 3 feet and prune lower branches of trees up to 7 feet.
Lighting is an important element in any site design. Good lighting will help people feel more comfortable with their surroundings. Lighting should provide clear paths for movement and highlight entryways without creating harsh effects or shadowy hiding places. Design lighting systems for pedestrians which enable people to better see one another and reduce the potential risks of nighttime walks. Remember to ensure that lighting is not obstructed by trees.
Additional Considerations:
- Signs and address numbers not only define the property, but also assist first responders.
- Control how your facility or business is being accessed. Limit ingress and egress through a controlled access point.
- Ensure secondary doors have adequate peepholes (180-190 degree view) and security strike plates.
- Ensure windows are properly secured to include using anti-slide/anti-lift devices.
- Ensure exits are properly marked and easy to locate.
- Surveillance cameras serve two purposes, as deterrence, as well as assisting investigators in the event a crime has occurred. Regular maintenance should include checking surveillance cameras and security alarms to ensure they are functioning correctly.