United by Light

In celebration of Earth Day, we’re going “dark” to shed light on the promise of the connected city. Geoff Manaugh of BLDGBLOG and GE collaborated to look at how San Diego’s smart lighting grid is leading cities into the future.

GE with Geoff Manaugh

San Diego is an interesting city to choose for launching an urban-scale lighting experiment, as it already includes an entire neighborhood named after its streetlights: The Gaslamp Quarter. In a sense, light is already a key part of San Diego’s urban identity.

Soon, though, San Diego’s streetlights will become intelligent: able to communicate wirelessly with one another, relaying real-time traffic information directly to cars and smartphones, even helping to plot better or more interesting routes across town. In the process, the city will gain a whole new feature, able to showcase unprecedented lighting effects using smart illumination and less electricity. This will turn something as simple as an evening walk into a true public spectacle, shared by all.

As these transformations unfold, urban infrastructure will take on a new and exciting public role, engaging the attention of residents by illuminating aspects of the city that had previously remained disconnected or unseen. This could inspire different uses of the downtown core, adventurous new routes from one part of town to another, or simply curious new visits to unfamiliar neighborhoods that have been transformed by the benefits of smart technology.


The association of San Diego with its streetlights will no longer be just a historical reminder of an old neighborhood — it will be a glimpse of the future of cities, and it will literally be something to watch.

Taking a Step Toward the Connected City

The new smart lighting system currently being debuted in San Diego is called LightGrid™. It comes from GE, it uses dimmable, GPS-tagged LEDs, and it brings massive energy-savings implications along with it. The variability of each LED also means that the streetlight network can be used to produce entirely new lighting effects throughout the city, trimming public electricity bills, increasing city safety, and fundamentally transforming how our streets look and feel.

Of course, this doesn’t just mean reducing light for the sake of pinching pennies: as it happens, cities are often guilty of using far too much light, based on outdated standards, effectively flooding their streets with ill-spent taxpayer money and wasted electricity. Not only do dimmable streetlights help to cut waste; they also help to bring urban light levels back to within a realm actually appropriate for human eyesight.

Seeing as it’s Earth Day, it seems particularly appropriate to emphasize the knock-on environmental effects of a system like this. Almis Udrys, director of Performance & Analytics for the city of San Diego, explained to me that, even with only one-tenth of San Diego’s streetlights now replaced by the GE system, the city is saving 2.5 million kilowatt hours a year — or more than $254,000 annually in energy and maintenance costs. He compared the accompanying decrease in greenhouse gas emissions, due to the system’s energy efficiency, to eliminating 4.1 million miles of passenger vehicle trips. These sorts of savings will only increase as the full functionality of the system is tapped.

However, on a larger and more interesting scale, the LightGrid™ system remains an open platform: in other words, it is just the first step toward a total reconfiguration of urban infrastructure, eventually adding wireless connectivity and computational power to the most basic fabric of the metropolis.

You’ve undoubtedly heard the phrase “smart city,” but that intelligence starts quite simply: with the waking up of things and spaces all around us, starting with light.

As Udrys phrased it, San Diego is “turning our inanimate objects into animate objects” — making them into connected nodes in an urban-scale computational network that foreshadows a future metropolis where it’s not just lights that are intelligent, but where objects, things, and spaces are all in dialogue together.

Udrys pointed out the lights are really just the foundation for a more ambitious, urban-scale data network that can be used to fulfill the Climate Action Plan set by Mayor Kevin Faulconer. Future features currently being tested with another intelligent LED system, also in a pilot phase in San Diego, mean that there could even be direct compatibility between the city’s streetlights and residents’ smartphones. These would mean the ability to inform drivers when and where they can park downtown, tip cyclists as to where they can lock-up their bikes, and even warn pedestrians if there is, say, an ozone alert and they should consider going back inside.

Those features might sound minor, but it is those sorts of features that could dramatically reduce the time cars spend driving around downtown, further cutting air pollution and greenhouse gas emissions in the process.

Another anticipated side effect is that, as the system continues to be upgraded and given wireless connectivity, one of its most useful features will be in helping plan more efficient maintenance routes for city repair crews. This will make maintenance both more streamlined and much cheaper. For example, the system’s wireless connectivity would mean that each streetlight could report its own status; further, because city engineers will have the lamppost’s exact GPS location, each pole can then be precisely mapped alongside other lights that need fixing. The city will no longer have to rely on angry members of the public calling in to report broken streetlights, or simply hoping that a repair crew happens to drive by and notice a damaged light. Udrys explained that this means “our streetlights will ‘tell us’ when they are in need of repair or replacement.”

Udrys was perhaps most enthusiastic about the ways in which LightGrid™ remains an open platform, one that is adaptable to future augmentation. It is just one part of a much larger, multi-year smart city initiative, he emphasized, the first small step along the way.

But, of course, that’s all just press release material; in that sense, it’s no surprise that this would sound so optimistic. I wanted to get a better sense of what the system really entails, and where it might be headed in the years to come, so I got in touch with Rick Freeman, GE’s General Manager of Intelligent Devices, to learn what might be at stake as cities transition to a much finer-grain control over their streetlights.

Giving the Grid Its Future Superpowers

I asked Freeman what sorts of effects, beyond just saving energy and keeping the city a bit dimmer at night, GE’s new variable light controls might have. In other words, if the city can selectively dim certain streets or neighborhoods — or, for that matter, flood them with light — what sorts of ends would this achieve?

Freeman answered by outlining a handful of speculative scenarios that showed just how much more value cities could be getting out of their streetlights. Importantly, Freeman was also careful to emphasize that most of these services have not yet been implemented — that the system is still being broken in, and that new amenities and features will still be rolling out over the next 12–16 months, some of them perhaps not for several more years.

However, quite a few of the potential services are genuinely interesting and worth bringing into the discussion. In a sense, Freeman was describing the total rethinking of what streetlights are even for.

Take emergency services. Someone on your street has had a heart attack, say, or there is a gas leak inside someone’s house: because each and every lighting node in the system is tagged with GPS, that 911 call or your neighbor’s report of a gas leak could be wirelessly coordinated with the nearest streetlight poles outside the address. The corresponding lights could then be selectively and rhythmically dimmed — from 100% to, say, 60% capacity — marking the precise spot for an ambulance or repair crew. Even if this only shaves sixty seconds off the ensuing response time, it might be enough to save a person’s life.

I asked Freeman how this might scale-up: if you could get an ambulance to a specific house somewhere in the city, could you steer an entire crowd out of the downtown core? Surely, you could use the lights as a navigational aid? Freeman used a large public sporting event as the prime example. Everybody’s getting out of a Padres game at the same time, he said — how do they get them all back to their cars most effectively, or, for that matter, how could you steer people toward the restaurant district using urban lighting cues? He suggested that it’s exactly this sort of thing that the system would be perfect for — that city events could be selectively lit for navigational purposes or even dimmed for interesting atmospheric effects.

This could mean turning San Diego’s famed Gaslamp Quarter into a de facto island of brighter lights, for example, a tempting destination more easily seen by all the people spilling out of the nearby baseball game — but, more interestingly, it could mean specifically lighting certain streets or pedestrian pathways to help guide people along these routes.

There are obvious questions to ask here: who controls these lights? Who makes the decision about what gets dimmed or brightened? Could one business district win out over another in terms of being chosen for these alluring light effects? More importantly, if people can be deliberately led away from particular neighborhoods, what are the long-term cultural or economic implications of this? Of course, these are less technical questions than they are political ones — but they need to be asked, and they are sure to pop up in the future.

Here, Freeman actually took our speculation a bit further. Taking a few steps beyond the current LightGrid™ system to look at what might be possible with the company’s future connected LEDs, Freeman pointed out that different cities will have different needs for intelligent lighting technology, but that the system will be able to accommodate a variety of remarkable scenarios.

Consider hurricane evacuation routes: rather than simply trust that drivers will have noticed all those evacuation signs posted along certain streets and highways leading out of town, the streetlight system itself could become both a warning sign and a directional network. In other words, if a hurricane evacuation has been announced, it could be accompanied by streetlights gently strobing every few seconds, indicating that something very bad is on the way; further, the actual evacuation route itself could brighten or otherwise be marked as the safest corridor out of the city.


Here, Freeman used the metaphor of airplane floor lighting. What if a similar idea could be implemented at the scale of an entire city, for pedestrians? The streetlights could then be used during an emergency to guide people away from the beaches, for example, if there’s been an earthquake at sea or a tsunami warning, or out of a particular neighborhood altogether, if there’s been a major fire or even a terrorist attack.

Of course, why wait for an emergency? This sort of directional system could easily be implemented as a regular and permanent part of a city’s pedestrian infrastructure, offering better directions, clear routes, and an increased sense of public safety for people walking across town at night.

City of Stars and Ecosystems

From Freeman’s perspective, the benefits of intelligent lightings systems will make them their own best advertisement. Other cities will literally see the difference and thus seek to incorporate this sort of network at home. If San Diego can boost bar and restaurant traffic downtown through subtle lighting cues, for example, saving hundreds of thousands — if not millions — of dollars in the process, other cities will want in on the action.

In fact, the benefits will not just be financial or environmental. As Paul Bogard writes in his 2014 book The End of Night, nocturnal light pollution also has very real health effects. Cities aren’t just burning taxpayer money or contributing to climate change by over-lighting their streets at night; they are also keeping us awake and interrupting our natural circadian rhythms. Stress and chronic sleeplessness can be seen as unintended side effects of ill-designed urban street lighting regimes, something that could, in theory, be addressed by variable dimming.

And that’s just the effect on humans. Wildlife and plants are also affected by the wasteful over-lighting of our cities, towns, and campuses. Reducing the light load we all bear at night by even as little as 10% is thus an act with potentially huge consequences — not only for us but for the crowded ecosystems we share our cities with. To discuss these sorts of perks on Earth Day is thus quite fitting.

It’s also worth noting that a more intelligently lit city is a place where you can better see the stars. The “dark sky movement” has long recognized this, urging cities to cut down on their nighttime electrical use not only to de-stress the wildlife in our midst, but so that we can all begin to appreciate the other, more important light show so many of us usually miss: the stars and constellations blurred out by urban light pollution.

While San Diego is a long way from becoming a dark sky city — and, in fact, this is not one of the LightGrid’s™ stated goals — it is nonetheless a tantalizing vision, that you might soon be able to enjoy the stars, find your way home faster on more efficiently lit roads, and pay fewer tax dollars for the privilege.

United By Light

So what do I, personally, hope that GE does with the system? It is easy to be optimistic, as the press material is exciting and the benefits clearly stated; indeed, the kinds of future effects described here, even if they shade over into sci-fi, are nothing if not seductive. But it would be a shame if this new technology, something so genuinely promising, is used simply to increase a city’s parking lot efficiency or to steer sports fans toward a nearby bar. Cost savings and environmental effects are amazing, of course — but cities should not stop there. Indeed, it is one of Mayor Faulconer’s stated goals to bring wireless capabilities to other systems and objects, and that a smart street lighting program is just the beginning of a much larger, fundamental change in the becoming-intelligent of the city.

What needs to be emphasized, however, is that a flexible light grid represents a genuinely historic opportunity for cities to rethink what urban infrastructure can actually do — including who, and what, intelligent infrastructure is for, in the first place.

If rethinking a city’s lighting system from the ground up can be used to make those cities more pedestrian-friendly, for example, encouraging us all to leave our cars at home for a night; if intelligent, adaptable lighting can encourage families to step outside for a walk together under the stars, rather than stay home alone for another evening; if connected LEDs could make bike paths safer, easier to follow, and more temptingly lit; if smart urban infrastructure can bring people out into the parks or beaches at night, perhaps using the airplane floor lighting effect that Rick Freeman speculated about earlier, then our cities can hopefully transform themselves by design into a totally different kind of public space. They will become true communities, connected by their infrastructure and united by light.

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