Nowadays consideration to security and ways of its increasing is a critical priority of urban planners. Although there is many theories about urban crimes, but the idea of effect of urban physical development on urban crimes is an important subject that new theories of urban planning considerate that. We can analyze urban crimes from different aspects. One of these aspects is reasons and factors cause a crime. Totally all of reasons and approaches can divided on 7 included: selective approaches, biological approaches, psychological approaches, social psychology approaches, sociological approaches, ecological and population approaches, and environmental design approach. The newest and recently theory among all of them is environmental theory or CPTED (crime prevent toward environmental design), that favors of this theory belived that urban design, building form and housing pattern types have a critical impacts on number and type of urban crimes. Hence, they are looking for ways to upgrade security using some changes in envronmetal design.
At the present paper the main framework is CPTED and the subject is to study correlation between number and type of crimes and high rise buildings or compactness and also recognition of crime hot spots in 22 zones of Tehran. After studying the theories and approaches about urban crime and security, we studied history and background of building high rise houses and towers in Tehran, that statistics and studies show that building this sort of houses started since the early 1960s in Iran and specially in Tehran, so, after that decade they are increasing always in all zones of Tehran metropolis.
Results and Discussion
Therefore, now according to ministry of housing and urban planning, there are more than 50000 high rise buildings. In the next step of research, for studying relation between two variables, some indicators are used. The indicators of urban crime are homicide, plural discord, two- person discord, burglary, social bad treatments, document impersonate, spoof, and the indicator of making high-rise are the number of high-rise building, the number of apartments and house density. It is a reality that although in comparison with other metropolitan areas in all around the world, Tehran is more secure and the number of crimes is lower than most of them, but in comparison with other cities in Iran, Tehran is the most unsecure city and this city devoted majority of budget of military and administrative forces for increasing security. In addition to this, we have to consider this point that because of special situation and role of Tehran in official and political system of Iran and leader of national economy, every kind of insecurity in this city might create a big crisis and risk for national security.
The concluded results confirm that change of life style and consumption pattern in Tehran and its outbreak in building and houses type, it means transition from one floor and one family house to traditional to living in apartments and high rise building and huge towers has an enormous effect and impact on number and type of insecurity indexes and factors. The findings show that there is meaningful correlation among these indicators. So, the zones with more high-rise buildings overlap with the zones of full of crimes. The statistical results of SPSS analyses stated that the correlation coefficient and drawled regression confirmed the findings as well In the other word, Tehran zones where have more apartment and high rises and more compacted, at the same time the most unsecure parts and have more number of crimes. So, in connection with building vertically and huge towers, lots of factors like social, economic, cultural, environmental, physical and technological factors are deal with. This phenomenon is using in western countries as well, but in those countries, there are some regulations and rules that decrease negative effects of them. But, in Iran, because of huge immigration from rural to cities, demand for building this form of housing in increasing and lack of attention of legislations and regulations appeared big troubles and problems. As a matter of fact, although high rise building and apartments affect urban security as the result of this paper showed in regions of Tehran more apartments and more towers, more crimes and more insecurity, but the main point is that pay attention to criteria and regulations in the time of building can decrease many related problems. It can be concluded that, in the subject of urban security, we should not only attention to the police and its role in making more security, but also, we should attention to effective factors on the number of crimes and presentation of some resolution for decreasing crime rate using environmental design and housing patterns.