Note this page includes general FAQs (below) and technical FAQs (further down the page).
- Why is The City of Calgary retrofitting residential streetlights with new lower wattage, flat lens fixtures?
- What does the word "retrofit" mean?
- What is light pollution?
- Do the lower wattage fixtures produce less light?
- Will lower lighting levels increase crime rates and increase the need for lighting on private property?
- If retrofitting streetlights to lower wattage is not a safety concern, why are parks and playgrounds excluded from the retrofit project?
- How is the project being funded?
- Will the retrofit cause my taxes to go up?
- Why did The City begin the citywide retrofit in northwest Calgary?
- When will the rest of The City's residential streetlights be retrofitted?
- Why is ENMAX the contractor for the retrofit project? Why aren't you using city crews?
- What will be done to prevent traffic disruptions on residential streets during the retrofit?
- How is The City informing residents about the retrofit in their neighbourhood?
- How long does it take to retrofit a streetlight?
- What about streets with trees that 'leaf out,' creating areas of darkness?
- What has The City of Calgary done with all the old streetlight fixtures that were removed during the retrofit?
- Wouldn't it have been more economincal to simply replace the old lights as they burned out instead of doing them all at once?
- Can I get a light installed in the back lane behind my house?
1. Why is The City of Calgary retrofitting residential streetlights with new lower wattage, flat lens fixtures?
The streetlight system is Calgary's single largest electricity consumer. When energy prices reached an all-time high in January 2001, Roads needed to find a way to reduce the cost of operating the streetlight system. Lower wattage fixtures consume less electricity, which will help keep operating costs down. Once the project is complete, The City will save approximately $1.7 million a year in electricity costs.
2. What does the word "retrofit" mean?
The term "retrofit" refers to the process of altering a mechanism (in this case streetlights) with new components that enhance safety and/or the environment and offer financial benefits.
3. What is light pollution?
Light pollution is wasted light. It can be recognized as sky glow (the glow above cities at night), light trespass (unwanted light going onto private properties) and glare (harsh, bright light shining into the eyes).
4. Do the lower wattage fixtures produce less light?
Streetlights with lower wattage, flat lens fixtures will generally appear dimmer. However, motorists will likely notice an increase in visibility because of reduced glare. The new lighting levels meet minimum Illuminating Engineering Society (IES) guidelines for safe residential lighting.
5. Will lower lighting levels increase crime rates and increase the need for lighting on private property?
The Calgary Police Service carried out a literature search of other jurisdictions and a crime stats review of northwest communities before and after the first stage of the retrofit. Although further study was recommended, results showed that the vast majority of communities did not experience an increase in reported offences after the lowering of streetlighting.
The primary purpose of streetlighting is to provide safe levels of lighting for sidewalk and roadway users. It is more appropriate for property owners to ensure lighting and protection of private property through, for example, the use of timers and motion sensor lights.
6. If retrofitting streetlights to lower wattage is not a safety concern, why are parks and playgrounds excluded from the retrofit project?
Under the guidelines used to determine the scope of the retrofit project, some streetlight locations, such as those frequented by children, require special consideration and may not be retrofitted at this time. Special locations include:
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In front of playgrounds;
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In front of parks;
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Roads and intersections where the spacing between the streetlights is too great to allow acceptable lighting levels to be maintained; and,
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Poles with decorative streetlights.
7. How is the project being funded?
The citywide EnviroSmart Streetlight Retrofit Project will cost an estimated $6.6 million. This project is receiving funding of $3 million from three levels of government – federal, provincial and municipal – under the Infrastructure Canada–Alberta Program (ICAP). The remaining costs will be recovered from savings associated with reduced electricity consumption and the elimination of group relamping.
8. Will the retrofit cause my taxes to go up?
Part of the funding for the EnviroSmart Streetlights Project will come from cost savings associated with reduced energy consumption and the elimination of scheduled group relamping. (The old residential streetlights in The City of Calgary were relamped every five years.) By retrofitting streetlights on a cost-recovery basis, this project will not increase taxes.
9. Why did The City begin the citywide retrofit in northwest Calgary?
Streetlight fixtures in northwest Calgary were due for group relamping in 2001. The City of Calgary, Roads decided to eliminate the expense of relamping the old dropped lens cobrahead fixtures in favour of retrofitting them with lower wattage, flat lens fixtures.
10. When will the rest of The City's residential streetlights be retrofitted?
The City of Calgary, Roads began retrofitting 7300 streetlights in northeast Calgary on May 12, 2003. The City expects to complete the northeast retrofit by the end of September 2003. Further retrofitting will proceed on a quadrant-by-quadrant basis until the project is complete in 2005.
11. Why is ENMAX the contractor for the retrofit project? Why aren't you using city crews?
The City of Calgary, Roads tendered out the streetlight retrofit work. ENMAX won the contract through an open bidding process in a competitive environment. The City's own crews do not perform streetlight construction work.
12. What will be done to prevent traffic disruptions on residential streets during the retrofit?
The retrofit project is a mobile operation, with ENMAX crews working on streetlights for only a short period of time. The contractor will only proceed with the work once proper traffic controls are in place. The City of Calgary and ENMAX will make every effort to carry out the retrofit work in a safe and efficient manner in order to minimize traffic disruptions on residential streets.
13. How is The City informing residents about the retrofit in their neighbourhood?
The contractor installs signs in each community to inform residents that their streetlights will soon be retrofitted. An interactive map on The City's website shows anticipated start dates and actual completion dates for each community.
14. How long does it take to retrofit a streetlight?
It takes approximately 15 to 20 minutes to retrofit a streetlight, since only the fixture is being replaced.
15. What about streets with trees that 'leaf out,' creating areas of darkness?
If trees are blocking streetlights, no amount of wattage will penetrate down to the roadway. Trees situated on city property with canopies that touch streetlights or cause a reduction in lighting levels may need to be pruned. Residents can contact The City and the trees will be assessed. The City has no authority to direct the owners of trees located on private property to trim branches.
16. What has The City of Calgary done with all of the old streetlight fixtures that were removed during the retrofit?
The fixtures are disassembled and the components – glass, steel, aluminum, etc. – are then recycled. There are a number of pictures on the Web site that show streetlight components being readied for recycling. Some parts are even used for crafts. The old glass refractors can be used as pots and the ceramic arc tubes can be used for sharpening knifes. Representatives of Environmental Assessment and Liabilities at The City of Calgary presented a paper on our environmental monitoring program at the International Association of Impact Assessment Conference in Vancouver in 2004. This presentation generated a lot of interest and inquiries.
17. Wouldn't it have been more economical to simply replace the old lights as they burned out instead of doing them all at once?
No. If Roads had done this project by attrition it would have taken about eight or ten years, and it would have been very hard to manage. The City replaced the lamps in the old luminaires on a 5-year cycle. With the retrofit project, the whole luminaire, including the lamp is replaced. As such,the group relamping is not being done during the retrofit, which is resulting in increased savings. In addition to reducing light pollution and glare, The City also wanted to reduce the wattage of residential streetlights in order to reduce electricity consumption. The new streetlights will save The City approximately $1.7 million a year in energy costs once the project is complete. These savings ensure that the project pays for itself. Reduced energy consumption also results in reduced emissions from gas and coal-burning generators.
18. Can I get a light installed in the back lane behind my house?
Yes. For a one-time application charge and a monthly rental fee, residents can have ENMAX install and maintain a high pressure sodium luminaire (lamp) under ENMAX's Bright Night's program as long as there is an existing power pole in their back lane. Maintenance and light replacement is included in the monthly fee. Up to six neighbours can join together to split the monthly rental cost and determine where to install the light. ENMAX will evaluate the designated site for optimum light coverage and electrical safety. As with Calgary's streetlights, photosensitive cell turns the back lane lamp on at dusk and off at dawn.
To initiate a back lane light rental agreement, contact 3-1-1.
Technical FAQs
The City of Calgary has received enquiries from all over North America regarding the technical details of the EnviroSmart Streetlights Retrofit Project. The following questions and answers provide information on many of the technical aspects of the project, including the lamps, luminaires, lighting levels, light pollution and Calgary's streetlight system.
- What type of new fixtures are being used in the EnviroSmart retrofit?
- What type of lamp is being used with the above fixtures?
- What is the difference in wattage between the old and new fixtures?
- What lighting guidelines were used to determine post-retrofit lighting levels in lux?
- Has The City done its own field tests to determine whether the new fixtures meet IES guidelines?
- Has The City of Calgary considered using small target visibility to determine lighting levels?
- Can the old dropped lens "cobra head" fixtures be retrofitted with flat lens glass to make them a suitable full cutoff fixture?
- Is The City of Calgary retrofitting with single or dual arc tube lamps?
- How is The City of Calgary determining which streetlights will be retrofitted?
- Which roads are included in the retrofit?
- Is The City installing extra poles where spacing is deemed too great?
- How close together do poles need to be in order to qualify for retrofitting?
- Will The City of Calgary retrofit lights in back alleys?
- How serious is Calgary's light pollution problem?
- Does The City have a benchmark for watts per square kilometre?
- Is The City addressing light pollution problems in other ways?
- Is The City developing a light pollution bylaw? Will it apply to all existing light pollution?
- What type of lamps does The City currently use?
- When do the streetlights in Calgary turn on and off?
- Does the retrofit project affect the whole city?
- Does The City of Calgary install streetlights on utility poles?
- Has The City of Calgary conducted an energy audit of the streetlight system? What advice would The City give other municipalities interested in conducting an energy audit?
1. What type of new fixtures are being used in the EnviroSmart retrofit?
The fixtures used in the retrofit are the flat lens version of the "Cooper OVH" series made by Cooper Lighting of Mississauga, Ontario. (For more information, visit www.cooperlighting.com/brands/streetworks 
and click "Roadway.")
2. What type of lamp is being used with the above fixtures?
EnviroSmart streetlights use high-pressure sodium (HPS) "Lumalux/Eco" lamps made by OSRAM SYLVANIA. (For more information, visit www.sylvania.com ). Most of Calgary's residential streetlights already contained HPS lamps before the EnviroSmart project began. The City retrofitted from MV to HPS approximately 20 years ago.
3. What is the difference in wattage between the old and new fixtures?
In general, the lamp wattage has been reduced from 200W to 100W on residential local roads and from 250W to 150W on collector roads. Depending on the roadway geometrics, the actual wattages may vary.
4. What lighting guidelines were used to determine post-retrofit lighting levels in lux?
EnviroSmart streetlights meet, wherever possible, the following illumination levels recommended by the Illuminating Engineering Society (IES):
- Residential local roads: Average illumination of 4 lux with a uniformity of 6:1 or better.
- Collector roads: Average illumination of 6 lux with a uniformity of 4:1 or better.
5. Has The City done its own field tests to determine whether the new fixtures meet IES guidelines?
Observance of IES guidelines is based on product design information. The City will measure the field results and have fixtures tested in independent labs to ensure that they are performing the way their photometric files suggest.
6. Has The City of Calgary considered using small target visibility to determine lighting levels?
The City of Calgary uses the luminance and illuminance methods to calculate design lighting levels. These are the IES recommended design methods for residential areas. Small target visibility is more applicable in the design of lighting systems for major roads and expressways.
7. Can the old dropped lens "cobra head" fixtures be retrofitted with flat lens glass to make them a suitable full cutoff fixture?
No. In addition to replacing the dropped lens or refractor of the fixture, the reflector inside the fixture must also be replaced to properly distribute the light spread from the fixture down onto the road. Since the new flat lens fixture is relatively inexpensive compared to the cost of performing this type of customization, it is more cost-effective to replace the old fixture with a new flat lens fixture of the correct photometry.
8. Is The City of Calgary retrofitting with single or dual arc tube lamps?
The City is using single "arc tube" lamps. We did look at the twin tube lamps but their use was not determined to be cost effective. The dual arc tube lamps have a rated life expectancy that is 67% longer than the single arc tube lamp, but it is about 3 times more costly. The City is not pursuing this option at this time.
Questions about the EnviroSmart Project
9. How is The City of Calgary determining which streetlights will be retrofitted?
Roads is using The City's streetlight database (a Geographical Information System [GIS] application) to determine which streetlights will be retrofitted. The database is queried using location and pole spacing criteria.
The principle purpose of roadway lighting is to create a safe environment. In general, roadway lighting fulfills three specific functions:
- Provide visual guidance for vehicular traffic: Reduces nighttime accidents and their associated human and economic costs.
- Enhance personal safety: Fosters proper nighttime vision to reduce pedestrian/vehicle accidents; promotes a sense of personal security; supports police protection.
- Commercial promotion.
All design criteria for roadway lighting systems are based on the appropriate IESNA (Illuminating Engineering Society of North America) Recommended Practice (RP), Design Guide (DG), or Technical Memorandum (TM) documents. These design criteria establish appropriate lighting levels, visibility levels and uniformity ratios.
10. Which roads are included in the retrofit?
The retrofit applies to low volume, low speed roads in residential subdivisions. Park areas are excluded from the retrofit. Lights with decorative pole top fixtures will also not be retrofitted at this time. It is important to note that no new streetlight poles are being added. Existing streetlights are only retrofitted if they are spaced so that IES lighting recommendations are followed once they are changed out. We are not redesigning the layout of the streetlight system, as this would be cost prohibitive.
11. Is The City installing extra poles where spacing is deemed too great?
To date, no extra poles have been added. Lights that are deemed too far apart are not retrofitted; when they eventually fail, these lights will be changed to flat lens fixtures of a suitable wattage. If the spacing is too great, we cannot use flat lens luminaires because these fixtures cover a relatively small area. If we did retrofit two such lights with flat lenses, there would be a dark area halfway between them and the Uniformity Ratio requirement would not be met. We would like to retrofit as many lights with cut-off fixtures as we can. But we have to meet our design criteria.
12. How close together do poles need to be in order to qualify for retrofitting?
Generally, poles affected by the current retrofit are davit type, 9 metres in height with a 2m overhang. Streetlights are retrofitted to lower wattage, flat lens fixtures if they meet the following spacing criteria:
- Residential roads: 61 metres
- Collector roads: 52 metres
These distances are guidelines only; field verification is required in some cases to confirm retrofitting eligibility where anomalies and special circumstances exist. In cases such as the end of a cul-de-sac, due to the inherent lower speeds and volume of traffic, reduced lighting levels and uniformity levels are acceptable.
13. Will The City of Calgary retrofit lights in back alleys?
In general, the City of Calgary does not light up its back alleys and lanes. However, any lights in back alleys will be retrofitted if they are cobra head fixtures owned by The City. Lane lighting is a revenue service offered by The City of Calgary's electric utility, Enmax, through their Bright Nights program. Homeowners who participate in this rental lighting program in their lanes will need to contact Enmax directly for retrofitting.
Questions about Light Pollution
14. How serious is Calgary's light pollution problem?
Pre-retrofit satellite images show that Calgary loses up to ten times the amount of light energy into space than other cities such as Vancouver, Victoria, Seattle and Portland. It is estimated that one-third of the light from the old streetlights ends up lighting up the sky.
15. Does The City have a benchmark for watts per square kilometre?
Although The City does not currently have citywide benchmark data in terms of watts/km2, the ongoing development of The City's GIS will make it possible to collect information such as watts per lane/km and watts per square metre of roadway in the future.
16. Is The City addressing light pollution problems in other ways?
Later this year, The City of Calgary will be launching pilot projects to test the feasibility of reducing the wattage for non-residential streetlights from 400 watts to 310 watts, and from 1000 watts to 750 watts along major roads.
17. Is The City developing a light pollution bylaw? Will it apply to all existing light pollution?
Bylaw Services is in the process of drafting a Light Pollution Bylaw for The City of Calgary. Existing light installations will likely be given a period of time to comply and/or may be grandfathered until replacement is required.
Questions about Calgary's Streetlight System
18. What type of lamps does The City currently use?
Out of approximately 73,000 streetlights in The City, about 71,000 are high pressure sodium lamps. The rest are a mixture of mercury vapour, metal halide and fluorescent, depending on the area of the City.
19. When do the streetlights in Calgary turn on and off?
The City's streetlight circuits are controlled by approximately 7000 photoelectric cells that sense the amount of ambient light. There are generally 8-12 lights on each circuit. In general, light controls turn streetlights on at 1 fc and off at 3 fc, which closely approximates a dusk to dawn operation of the streetlights.
20. Does the retrofit project affect the whole city?
Since 2001, the standard for new streetlighting in The City of Calgary has been cutoff distribution, lower wattage fixtures, except in the case of decorative streetlights. The EnviroSmart Retrofit Project affects existing residential poles that were installed before 2001.
21. Does The City of Calgary install streetlights on utility poles?
The City of Calgary no longer installs lights on utility poles as these poles are owned by the utility and are not under The City's care and control. Remaining utility poles with attached streetlights are generally located in industrial areas and older areas of The City. When development permits come in for new industrial sites, The City installs stand-alone streetlights whenever possible.
22. Has The City of Calgary conducted an energy audit of the streetlight system? What advice would The City give other municipalities interested in conducting an energy audit?
An engineering consulting firm helped Roads with the initial analysis of the existing streetlight system and the cost benefit/analysis and detailed design of the proposed retrofit. Roads did not do a terms of reference and energy audit proposal call. For municipalities wishing to do so, a good starting point might be to contact their streetlight or energy provider and see if they will conduct an energy audit free-of-charge. Beyond that, an outside consultant would be able to provide this service for a fee.
