For all of the automation that exists in today’s urban environs, few cities have a system of mapping urban streetlights, or of tracking whether or not they are operational. This means that, if a light goes out, it must either be reported or observed by an inspector in order to be replaced. As a result, burned-out lights are rarely replaced promptly and when crews do go out to replace them, they may not have the necessary tools since they have little to no information about the lights that they are replacing (i.e. pole height, when the bulbs were last changed).
To address this issue, a team of researchers at MIT’s Department of Mechanical Engineering developed an inexpensive, automated system to monitor streetlights in collaboration with Spanish infrastructure contracting company Ferrovial, which manages street-lighting systems in several cities. The experiment was published in a paper in IEEE titled “Urban Street Lighting Infrastructure Monitoring Using a Mobile Sensor Platform.”
The system, which replaces manual inspections with vehicles topped with cameras and sensors, gathers information in much the same way that Google generates street views: by driving around at night and picking up the location of streetlights with digital cameras. The technology allows the software to distinguish between streetlights and other sources of light and to estimate the height of each lamp. Sensors also measure the level of illumination coming from each lamp to assess if light bulbs are weakening, in addition to measuring dark areas between light poles, indicating where poles might be needed to better illuminate the street.
The team, which includes Sumeet Kumar, Sanjay Sarma and Ajay Deshpande, among others, tested the equipment in four cities across Europe and America: Cambridge, Massachusetts, Malaga and Santander in Spain and Birmingham in the UK. In order to avoid incurring extra costs to cities, the team has proposed that the cameras and sensors be mounted on the roofs of vehicles that are owned by cities, such as police cars, buses and garbage trucks that already make the rounds.
The researchers found that, while many cities have turned to LED lights to make savings on the cost of electricity and maintenance, there has been no way of measuring the results of these savings in the absence of a monitoring system. Using a system such as this would allow cities to measure the impact of integrating cost-and-energy-saving technology into a city’s streetlights. Surveys like these could also potentially provide city officials with a comprehensive map of any given city’s light requirements.
Although the study specifically targets streetlights, researchers believe that the system – which includes a precision mapping system, algorithms for interpreting the information gathered from the cameras, and ways of capturing and storing the information – can be applied to other aspects of urban infrastructure.
“One interesting aspect of this work was the use of cameras to estimate the heights of the street lamps. … This type of information would be extremely useful for rapid inventory management,” Andrew Smyth, professor of civil engineering and engineering mechanics at Columbia University told MIT News (Smyth was not involved in the project). “With the general trend to more efficient and controllable LED street lighting systems, an improved knowledge of the current inventory and its effectiveness is extremely valuable. [This information can be used to not only] improve design of entirely new street lighting configurations but also assess the current performance of the existing systems, which may be under- or over-lighting in places.”