What impact do street lights have on a city’s populace? According to Washington, DC Mayor Muriel Bowser, street lights make the city’s streets “safer, stronger, and brighter.” This is the justification being used for the launch of a new service that allows residents of the district to report street light outages via text message. The challenge with city street lights is that they have a greater impact on how citizens feel than on more quantifiable measures.
The conventional wisdom says that brightly lit streets reduce crime and traffic collisions. Yet, a 2015 study published by the Journal of Epidemiology and Community Health found little evidence of harmful effects of reduced levels of street lighting on road collisions or crime in England and Wales. Researchers analyzed 14 years of data from 62 local authorities that implemented strategies such as switching lights off permanently, reducing the number of hours that lamps are switched on at night, dimming lights, and replacing traditional orange lamps with energy efficient white light LED lamps. Empirically, permanently switching off lights did not lead to an increase in crime or car crashes.
But it is too simplistic to conclude that better street lighting has no impact on a community. Another study, this one published in Safety Science, found that well-lit streets make pedestrians feel safer. Politicians, the ones who often shape street lighting decisions, get elected by what the electorate feels to be true, not what actually is true. Moreover, advanced control of street lights can reduce energy and save money.
Where DC Gets It Wrong
Washington, DC’s street light outage monitoring plan relies on residents reporting which of the city’s 70,000 street lights are out. At one point, crowdsourcing a problem like this was innovative; the ubiquity of smartphones and other connected devices only recently permitted such engagement. But, as noted in Navigant Research’s Outdoor Lighting Systems report, adding controls and communication networks to street lights enables municipalities to reduce energy consumption and make monitoring and management more efficient.
The City of Oslo, Norway faced the same challenge in 2010 (back when crowdsourcing was still a thing). The city relied on reports from residents to identify street light failures for its 55,000 street lights. Oslo wanted to make repair crews more efficient and also be able to reduce light levels as needed. In response, the city connected its street lighting into a single remotely accessible network that allows monitoring and control of light levels through Internet-based applications. The move reduced energy use by 62% while also reducing lamp downtime.