NEC says it has deployed an AI-based traffic monitoring system to Central Nippon Expressway (a.k.a. NEXCO Central) that uses fiber optic sensing and AI to visualize traffic conditions – such as the location, speed, and direction of travel – by detecting vibrations produced by vehicle movement.
Highway operators already use sensors to monitor traffic flow and detect incidents on expressways, but most sensors for this kind of use case are point sensors or cameras with a limited field of view. Using these kinds of sensors is inefficient and expensive, as well as an installation/maintenance headache, because it takes a huge number of them to perform continuous measurements over a wide area.
NEC’s traffic monitoring system makes use of existing optical fiber communications infrastructure along highways, with sensing devices attached to one end of an optical fiber that measure road vibrations from passing vehicles.
According to NEC, the traffic monitoring sensors send that vibration data to an AI engine in the backend that converts the data into continuous vehicle trajectories along roads, which makes it possible to constantly visualize traffic conditions along the entire road, and detect accidents and congestion earlier.
From the release:
The newly developed analytical AI engine can extract vehicle trajectories from vibration signals in the presence of multiple environmental noises. Vehicle trajectories are extracted in an iterative process. First, the clearest vibration signals are used to extract vehicle trajectory, then the corresponding signals are masked. Second, the remaining vibration signals are enhanced. The system repeats these two steps until all the vehicle trajectories are extracted.
NEXCO Central is reportedly the first expressway operator in Japan to use the traffic monitoring technology. NEC and Verizon conducted a proof-of-concept field trial of AI-powered road traffic monitoring using existing fiber optic cables in 2019.
NEC is promoting the AI traffic monitoring solution as part of its overall digital transformation solutions for road operators under its “NEC Safer Cities” initiative.