The ability to turn lights off automatically when they are not needed is a proven energy saver, whether it is a single porch light or a campus-wide area. The basic requirements for an automated lighting system include:   

• Sensors that accurately measure the need for lighting (based on daylight, occupancy and time of day).
• A control system that adjusts the lighting based on sensor input.
• Lamps that can be turned off and on frequently in response to occupancy without negative impacts (such as greatly shortened lamp life).
• Fixtures with integrated sensors and controls are available. In large systems, a networked control strategy can be used for all fixtures and be controlled by computer if software and appropriate communication channels with the lighting fixture are incorporated. 
     

Wireless controls are making installation easier than ever. Wireless networks can include other functions such as traffic lights, smart grid/smart city projects, and traffic data. Drawing a line between components gets fuzzy with integrated components and systems that are mostly proprietary (as of early 2013). At least one product, Illuminating Concepts from Intellistreets includes poles as part of the system and options that can assist Homeland Security or other operations with crowd control and emergency information. This system can also provide advertising space that owners can use to help pay for it. This product was named the IES lighting control Innovation of Merit Award winner in January 2013.

Standard practice for controlling most area lights is to use dusk-to-dawn control sensors mounted on each unit. Time clocks are fairly common where there is a predictable schedule. Dimming and motion detectors have been limited in the past to use with incandescent or fluorescent lighting systems due to the slow response of HID systems unless a bi-level ballast is used. Halogen lights controlled with motion sensors are fairly common for residential entry and driveway lighting, where the area covered is relatively small. Standard wall switches are still common at entryways or loading docks at many facilities.

High-performance fluorescent lighting systems, electronic ballasts for HID lighting and LEDs are making more refined outdoor lighting controls possible in more applications. Fixtures with integral controls beyond just a simple photocell are now available.

The old standard – dusk-to-dawn photocells – are available in models that are on about half the night; these shut off in the early morning hours then turn them back on before dawn if activity is expected at that time. Photocells are manually programmed or have onboard controls that calculate how long the darkness should last, shut the lights off and then turn them back on at a set time before dawn.

Electronic ballasts are making dimming possible in increasingly higher wattages for HID systems that were previously limited to high/low operation in conjunction with occupancy sensors. Strike and re-strike times are still a factor in systems where the lights turn off completely.

LED fixtures can be switched frequently, illuminate instantly and are available with integral controls. Longer-lasting and more durable sensors are available and are still evolving. The latest technology on the scene is "fixture-integrated cognitive sensor/controllers."  They have sensors built into the luminaire that automatically responds to its environment – whether it's occupancy, available daylight, time of day or other variables – and deliver just the right amount of light when and where it is needed -- is the perfect solution for reducing energy consumption and costs. Rather than applying controls as an afterthought the built-in approach maximizes energy efficiency.

Mesh networks can operate multiple lights, transmit operating signals past non-functioning units and use two-way communication to report failures. Occupancy sensors are combining ultrasonic, infrared and even visual information to make their response more accurate. Units are being developed that can cover large areas from high mounting points in parking lots and other areas. Wireless technology makes retrofits and new construction installation easier, and comes as wireless infrared, radio frequency or powerline carrier systems.

The California Lighting Technology Center has installed a networked wireless adaptive outdoor lighting control system using Lumewave controls and LumeStart control software. These controls are installed on a series Philips Lumec LED outdoor lighting fixtures and wallpacks and WattStopper sensors (daylight and occupancy) to calculate the occupants' direction of travel and turn the lights on and off relative to their position – a necessary function for traffic that moves faster than a slow stroll. Lighted areas invite people in while dark areas do not, so it is essential to light areas ahead of travel.   One example of this is a bike path on the UC Davis campus.  It is illuminated at night with a “just in time” system. One light node alerts another and another down the line as a bicycle goes by, progressively lighting the rider’s way, then dimming back into an energy-saving mode. (Barringer, 2013)

Lights that burn all night when they are not actually being used by people can negatively impact animals in the area and neighboring properties, and may increase skyglow, obscuring the view of stars in the night sky, particularly for astronomical observatories within range. 

The jury is still out on whether lighting unoccupied spaces thwarts, assists or has no impact on crime in the area. Occupancy sensors could alert security staff about the location of unwanted activity by brightening or turning on when someone enters the space. Sensors that are just emerging on the market may include video surveillance and the capability to signal or provide information during emergencies.

Mesh networks can control much more than street lighting, such as enabling better traffic flow and providing damage reports and emergency information. However, this aspect of information gathering and transmission may also prompt public resistance due to concerns about invasion of privacy. Before these types of features are included in a system, obtain public buy-in.

When dimming is involved with traffic lighting, it is important to sort out concerns about liability in case accidents or other negative activities occur. If units fail, the default setting should be “full on” rather than off or dimmed. 

For systems that use mesh networks to control each fixture alone or in groups, lighting can be adjusted for special events in only the area of the event while other areas remain dimmed. For systems incorporating color-changing capabilities, lights could be colored for special events or holidays and only in areas where it is desired. 

Much of the expected savings depend on the systems having a long life (which greatly reduces maintenance costs as well), but no installations in use have yet reached that expected end of life so there are still some unknowns. 

Greenhouse gas reduction is a benefit of reducing energy use.

First costs are still a barrier to new control strategies for outdoor lighting because they often include entire new lighting systems. Most current installations got funded when the Recovery and Reinvestment Act (ARRA) funds were available, but that program has ended. Paybacks tend to run above five years – close to ten for many installations if energy savings are the only basis used to calculate payback.

It is essential to find (and pay for) qualified help to put together a system that will meet the customer's needs. The task of sorting through the proliferation of products and marketing materials and understanding the components and their interactions can be challenging.

In late 2012, most control systems were somewhat proprietary and standards for interconnectivity were still in development. In late March 2013, ZigBee announced the completion and availability of the first open standard for an IPv6-based full wireless mesh network. A draft of a model specification for adaptive control and remote monitoring is out for comment now from the Municipal Solid-State Street Lighting Consortium. Once completed, this specification will provide some assistance in specifying these controls.

Potential buyers will need to:

• Determine when to invest in a lighting control system,    

• Determine its value, and

• Decide if they want the additional features that come with a proprietary system or wait for more interconnectivity and features to become standard and less expensive.

For municipal street lighting, potential buyers will need to:

• Determine if the projected energy savings will result in monetary savings, especially in light of tariffs;

• Decide if they should retrofit existing lighting or invest in a new system; and

• Train staff in operation and maintenance of the system.

Simple adjustments to existing equipment:

• Dusk-to-dawn photocell controls and enhanced half-night photocell controls.
• Stepped lighting reductions used with more conventional lighting that are controlled by time clock, starting with the most distant areas and moving closer in large parking areas.