Professors Help Brighten City Streets-Faculty & Staff News - Carnegie Mellon University

Wednesday, June 1, 2011

Professors Help Brighten City Streets

The School of Architecture's Remaking Cities Institute (RCI) is helping Pittsburgh with a bright idea.

City Councilmember Bill Peduto wants to replace all 40,000 of the city's streetlights with light emitting diodes, also known as LEDs.
What's enlightening about this plan is that the goal of the project is not only to save energy and money, but also to improve the quality of life in neighborhoods and business districts.

"The Pittsburgh model of LED street lighting is really going to be the brand of 21st century urban lighting," Peduto said.
Peduto said the idea goes back to the city's Climate Action Plan from several years ago when one of the major issues identified to reduce the city's green footprint was lighting. Around the same time, the Clinton Climate Initiative made outdoor lighting, which can account for a significant percentage of a municipal government's electricity usage, a priority.

With innovative new technologies, cities can raise the efficiency standard for outdoor lighting while quickly reducing greenhouse gas emissions and saving on energy costs.

"CMU's role was to think beyond the box and to create the model that has not yet been created for lighting for the 21st century, and beyond the parameters of what is currently available," Peduto said. "Pittsburgh electrified its streets in 1910. There hasn't been a great leap in urban lighting since then. This would be the next big stage."

Don Carter, director of the RCI, and a team of researchers will report to city council their findings later in June. Some of their proposed changes could revolutionize street lighting.

The city is looking at improving energy efficiency, reducing costs and improving the quality of life for drivers, pedestrians and bicyclists. Carter said other concerns were safer streets, less light pollution to allow for darker skies ?at night, and an emphasis on urbanism.

As part of their recommendations, the lampposts will remain, but LEDs will be retrofitted into the fixtures, and how lights are used in general may change.
Cindy Limauro, a professor of lighting design at CMU, and her partner at C&C Lighting Chris Popowich are part of the RCI team researching possibilities for the city. C&C Lighting also created the Pausch Bridge and Hunt Library LED displays.

A groundbreaking idea is having all of the lighting controlled from a central location so that lights in individual neighborhoods, or even streets, could be adjusted for color or intensity. Currently street lights come in a single color temperature. Dual color temperature allows for complete flexibility of preference in residential and commercial areas.

For example, business districts might want a warmer color temperature while a commercial district might want a cooler color temperature. Or, Limauro said, psychologically, the city might want to have warmer lighting in the winter and cooler lighting in the summer.

"We are excited," Carter said. "No one else in the world is doing this in terms of manufacturing design of street lights. People are the center of our study."

This is the first lighting project that the RCI has undertaken. It covers all aspects of the institute's mission of research and urbanism, education and regional impact.

"It will have international impact on lighting, and the prototype of the study is the city of Pittsburgh," Carter said.

The RCI team also is recommending color-changing tubes that would attach to the lampposts. Lights could be programmed for different festivals, celebrations and even emergency situations. For instance, during football season they could be gold or during festivals, they could direct people to different venues with blue or green pathways.

"Pittsburgh has branded itself as a city of art," Popowich said. "You could have many different strategies for using lights."
While manufacturers do not currently have this technology available for street lights, Limauro said they are excited by the possibilities and are willing to experiment. Orfield Laboratories in Minneapolis is also involved in testing the research.

"We're pushing the envelope of the industry itself," Limauro said. "Manufacturers are willing to work with us and are excited that cities are considering the quality of lighting and the aesthetics."

The first phase of the project is to install 3,000 LED lights in all the business districts of the city, which Carter said is expected to be completed by late February 2012. Pittsburgh received a grant of $816,000 from the Commonwealth of Pennsylvania to aid in the design and installation of the LEDs in the business districts.

The RCI team studied three business districts of varying size and character to develop technical criteria for the project: Fifth and Forbes avenues in downtown Pittsburgh; Carson Street on the South Side; and California Avenue in Brighton Heights. Peduto said that the new lighting will be equitable throughout the city business districts and neighborhoods.

The 37,000 remaining lights in the residential neighborhoods will be replaced over the next five to 10 years. Carter said the city anticipates a payback in savings in energy, maintenance and repairs five to seven years after each phase of installation.

By: Heidi Opdyke, opdyke@andrew.cmu.edu