7 Considerations before making changes to public lighting

by Gary Atkinson | Jul 24, 2017



As we have discussed here before, many, if not all, local authorities and municipalities are looking at reducing the cost of maintaining road and footpath lighting. Whichever option one looks at, it is going to require a visit by a two man crew to every lamp post at considerable expense and ideally, one does not want to have to do that again for at least 10 years. So before embarking on any lighting modifications, here are 7 things to consider that can ensure today's investment in money and time can bring the increase in value everyone is looking for:

  1. Part night lighting - a popular option today is turning lights off between 12 and 5am. It elicits a mixed reaction from the public and although the crime figures don't reflect it, there is a lot of anecdotal evidence that petty crime (not deemed important enough to report by the victims), like car vandalism, garden theft, etc., has increased. However, the big issue with part night lighting is that it does NOT necessarily save money. I wrote an earlier post on this but in essence; tariff rate can increase, lamps need replacing more often, part night lighting cells are 2 or 3 times the cost of a standard photocell and you also have to factor in the cost of making a visit to every post you want to change. You do get a reduction in CO2 as the lights are off but the financial justification is tenuous.
  2. Wholesale replacement program - another way to reduce operational costs is to roll out a mass replacement project to switch existing lanterns to something more energy and maintenance efficient. Currently that normally means LED, which has its own issues but we will get to that in a minute, but it could be newer and more efficient HID luminaires. However, the lighting estate will have a mix of lanterns of different models and ages and many perfectly good lanterns with plenty of life will be removed and sent to landfill. Upgrading lanterns with 10+ years of life left would reduce that waste.
  3. LED upgrade? - the cost justification for deploying LED is strong, especially with LED lantern prices reducing as they are but there are still many questions to be asked regarding the quality of the light they produce. A lot of recently deployed schemes are very harsh with a colour temperature over 4000k or higher. The uniformity on the road surface is not as good as what it replaced producing a zebra effect down the road and the glare from the lanterns itself can be temporarily blinding. Yes, ongoing costs for energy and maintenance will be lower but is it really an "upgrade"?
  4. Going LED but with no CMS (Central Management System = remote control of the lights) - many of the LED replacement programs that have taken place in the last 5 years have been a simple swap out with a low cost photocell to control the lights based on dawn and dusk. Such a program is a massive investment and it does seem a waste to not have spent a little bit more so that changes could be made in the future. As an example, the lights in my village have been switched to part night lighting but despite local support for changing the switch-off to be an hour later on Friday and Saturday nights, the council admitted that they could not make the change as they would have to visit every post again. There is also no override to switch the lights on if required by the emergency services which will hinder them in times of need.
  5. Deploying LED with CMS - Not all CMS are created equal. Yes, they will allow you to measure energy consumption of each lantern and report a fault with a fitting but there are many limitations too. Turning lights on and off via radio will always miss some units out and so they don't come on as required or they stay lit during the day. I would argue that they still need to function as a street light first with the network there for information retrieval - not direct control on a daily basis. The biggest limitation with current CMSs though is the potential they are wasting. They use low bandwidth technology that is not scalable for the future and although they talk about being "Smart City Ready", they just don't have the capacity for all the sensors that we would like to deploy. They are also not designed for local control so they can't be used for changing traffic signals based on real time congestion, for example.
  6. LED lanterns that are "Sensor Ready" - A number of new LED fittings have appeared on the market as sensor ready - i.e. sensors can be mounted in or on the lantern. They purport to offering a sound smart city investment as one can add sensors in the future but that is ignoring the significant cost of making return visits to each lamp post as none of the sensors exist yet. It also excludes measurement like air quality as measuring NO2 and O3 at 5-10 m above the ground is not representative - it needs to be between 2-3m or as low as possible without being in the reach of drunken students with a cricket bat.
  7. LED lanterns with integrated CMS - a certain well known lighting manufacturer is pushing a range of lanterns with its own built in CMS. These units come equiped with a cellular SIM card in them and the price you pay includes the data the lantern will use over a 10 year period. I am sure it is a very good CMS platform however it does miss one important point. It is not creating a network at ground level that the local authority can use for their smart city aspirations - unless they want to pay a monthly fee to one of the big 3 network providers for every device they deploy. Street lighting has massive potential to become the connectivity backbone for all sorts of sensors and controllers as it puts mains power in the street and you have a ready made aerial network. Give yourself options rather than limiting yourself to one manufacturer and their preferred mobile network provider.

If you are thinking of a lighting program to save money or reduce energy consumption, get in touch with us and we can discuss your choices. We offer a 3rd option that makes HID almost as efficient as LED, provides all the CMS capability you need but has been designed as a Smart City network to future proof your investment. Get in touch or download our brochure to learn more.

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