5 Ways to Turn Streetlights into a Powerful Public Safety Technology

Streetlights play an important role in creating safer streets – whether by preventing traffic accidents or reducing crime. The well-documented impact of street lighting on driver behavior, pedestrian visibility and criminal activity makes intelligent street lighting a critical public safety technology.

Poor lighting can cause glare and other effects that compromise road safety at night ^[1]. More intelligent lighting strategies can reduce fatal midblock crashes by over 50%. ^[2]

Cities have also seen a positive correlation between better lighting and a reduction in crime – prompting Memphis Mayor Jim Strickland to say, before turning on his city’s intelligent streetlights: “We will be bringing much needed and significantly improved lighting to every neighborhood in Memphis with these new lights. No longer will criminals have safe harbor to operate under the cover of darkness and prey on our citizens in dimly lit parts of the city.”

But what exactly does “improved” street lighting look like? We have studied the data and have found some best practices cities are employing to make lighting an important part of their public safety technology strategy.

1. Brighter isn’t Always Better

About 20 years ago, communities in the U.S. northeast converted highway lights from high-pressure sodium (HPS) vapor to LED technology. This made the lighting brighter and whiter. In winter, the new lights reflected off falling snow causing glare and other hazards. The takeaway: switching from HPS to LED isn’t a simple hardware swap. The luminance of LEDs needs to be fine-tuned to suit different situations.

Intelligent controls are essential to make that tuning possible. When Davis, California and Cambridge, Massachusetts citizens complained their lights were too bright, the municipalities did not have lighting controls, so they had no way to tune the lighting. They had to replace the systems at a considerable cost. ^[3]

Switching from HPS to LED isn’t a simple hardware swap. The luminance of LEDs should be fine-tuned to suit different situations.

2. Conditions Count

Most drivers know from experience that visibility is worst at dawn and dusk. The old saying is true that it’s always darkest just before the dawn; and at day’s end, light changes quickly and drivers’ eyes have trouble keeping up, which can impair their perceptions and reaction times. ^[4]

These facts make it important to adjust streetlights for time of day. Simple timers can easily get out of sync with actual sunrise and sunset, but smart controls allow streetlights to adapt dynamically — especially when GPS technology is integrated to map each light pole precisely to the Earth’s rotation.

Different types of roads demand different considerations when planning for the use of streetlights as public safety technology. Highways require illumination over distance. Streets in town, on the other hand, need to be lit so drivers can focus on the vehicles and pedestrians immediately around them — with extra light at intersections, which are typically busier.

Interestingly, some studies have found that uniform light — often a goal for street lighting design — may decrease road safety in certain settings. As one research paper put it, “...a mild degree of non-uniformity in road lighting may well help road safety as it can aid distance perception and provide an additional dynamic.” ^[5]

3. Public Safety Technology Should Protect Pedestrians

Street lighting that focuses more on the roadway than the sidewalk, or more on sidewalks than the road, can make it harder for pedestrians to see or be seen. According to research published by the U.S. Federal Highway Administration, environments with more visual clutter (such as cities) may need extra light compared to those with clearer sightlines and less visual distraction. ^[6]

That same study recommended vertical lighting patterns for areas with little pedestrian traffic and brighter, semi-cylindrical lighting for those that see more than 100 pedestrians per hour, with all light sources at a color temperature at least 3,000 Kelvin.

Smart lighting controls make it possible to customize the brightness of each light fixture along a stretch of road, creating gradients between fully lit intersections and the stretches that connect them, while ensuring both sidewalks and streets are sufficiently lit for driver visibility and pedestrian safety.

Environments with more visual clutter may need extra light compared to those with clearer sightlines and less visual distraction.

4. Intelligent Street Lighting Reduces Crime in Residential Areas

According to a report by the U.S. Department of Justice Office of Community Oriented Policing Services (COPS), improved streetlighting is an effective way to prevent crime. ^[7] Investments in intelligent lighting in high-crime neighborhoods deliver some of the biggest crime reductions. COPS found that improved streetlighting acts as a situational deterrent to crime and can boost community pride, which makes residents more willing to intervene. The study outlined several components to safer lighting, including choosing the right lamps, color rendering, optical controls, brightness settings, pole spacing and height, vertical illumination, and glare.

5. Fewer Outages = More Consistent Safety

Burnt-out streetlights and flickering lamps are distracting and pose safety hazards. Outfitting streetlights with smart sensors ensure lighting managers receive outage alerts right away.  Alerts can be set up for things like flickering lights, full outages, power sags and swells and pole knock downs. Knowing instantly and reliably when lights are not performing, supports better maintenance and faster time to repair, and relieves municipalities and utilities from needing to hire trucks to drive around at night looking for outages.

Streetlight Controls are a Key

Many communities recognize the importance of good lighting design and involve designers in pre-deployment planning. Combining smart design with advanced lighting controls makes it possible to solve public safety issues — and to optimize energy and cost savings, which are often the main drivers for upgrading to LED.

With the U.S. government ready to spend on next-generation innovation, energy efficiency, sustainability and community safety, municipalities are well positioned to implement street lighting as a public safety technology that will also bring down their long-term operating costs, decrease GHG emissions and make their cities and towns safer for all.

Government is ready to invest

Available public funding for street lighting and other smart city initiatives includes: