Thursday, August 5, 2010

LEDs - New technology to light up your life

Night-time lighting in many cities is awful


When it comes to safety on the street, we've talked about the role of walkability and lighting. Last week we talked about sustainability and green spaces in our civic DNA. Today guest blogger Randy Atlas introduces a new technology that combines natural surveillance with environmental sustainability.

Randall Atlas is a nationally recognized criminologist and architect specializing in CPTED. He is author of numerous publications about CPTED including his most recent book 21st Century Security and Crime Prevention: Designing for Critical Infrastructure Protection and Crime Prevention.

A similar version to this blog will appear in the upcoming CPTED Perspective newsletter.

The LEED rating system has become the driving force behind the green building movement in America. This program is a voluntary, consensus-based national standard for developing high-performance, sustainable buildings.

One of the most effective methods in CPTED is the use of natural surveillance. Natural surveillance limits the opportunity for crime by taking steps to increase the perception that people can be seen, thereby naturally reducing the risk of crime. Jane Jacobs formulated the natural surveillance strategy based on her work in New York’s Greenwich Village.

Nighttime lighting helps promote natural surveillance. A well lit parking lot or outdoor area is an extremely important feature of public spaces for numerous reasons. Not only does it deter crime and vandalism, it can attract customers, facilitate traffic and pedestrian safety, and increase economic development. Proper lighting provides an individual with choices on movement: whether to go forward or back from a particular area.

Lighting can also be energy draining and costly, harming the environment. The Light Emitting Diode - LED - is a new technology appearing in North American cities with superior energy efficiency and excellent lighting characteristics. LED also is more durable and has lower operating costs than traditional outdoor lighting.

New LED technology is so efficient it can light up sports stadiums


The Emerging Technologies Program of Pacific Gas and Electric Company in Oakland, California recently studied the applicability of LED luminaries in a street lighting application.

After concluding from the first phase that “no significant concerns (were) so identified” of the likelihood of any negative safety impacts from the installation of the LED luminaries on a public street, the project moved into the second phase. This involved the replacement of fifteen 121 watt high pressure sodium lights in an Oakland, CA neighborhood with the same number of new ‘Beta’ LED 78 watt lights from Ruud Lighting.

The results indicate that the LED lights drew an average 35% less power than the standard high pressure sodium lights used by most cities. Over the course of a year each LED light saves 178 kWh.

Lighting that is poorly planned may waste energy, decrease vehicle and pedestrian safety, and may result in light pollution. It is important first to identify energy efficiency and safety goals and then explore all the options, such as LED lights. That is the key for finding a proper balance between LEED and CPTED. It is also how we will improve urban developments and our way of life in future.