In a huge city, lighting the streets is a necessary but pricey precaution. Pedestrians and motorists are no doubt safer when streetlamps, not just car headlights, illuminate roadways and sidewalks - but streetlamps are expensive and inefficient to run.
A prototype system that turns the lights on and off depending on traffic could save money while preserving safety.
Researchers at the Institut Teknologi Bandung in Indonesia built a responsive streetlamp system that recognizes a toy car speeding past, and switches on automatically. Jakarta, the massive megacity at which this effort is aimed, has more than 200,000 street lights, which cost about $17 million to operate in 2007, according to their study.
Researchers Suprijadi, Thomas Muliawan and Sparisoma Viridi built a prototype automatic lighting system that consists of a video camera, a lamp, a PC and a toy car. The camera, shooting at 25 frames per second, captures a car and the computer processes the image to determine whether it's really a car.
The system recognized the passing toy car 91 percent of the time at speeds up to 2 mph, according to the paper, posted to the arXiv database and reported by Technology Review. The system's accuracy falls as the speeds increase, however.
There's plenty more work to be done to improve the system's sensitivity, as well as test how it would react to pedestrians and cyclists, and how it works in different types of weather. But it's a good first step toward a more efficient system for lighting the streets, as Tech Review points out.
A system like this could help reduce energy consumption in cities throughout the world. Then we won't have to worry about injecting trees with glowing nanoparticles.