Traffic noise in cities continues to be a major source of noise, greatly affecting citizens. To the city of Geneva, Switzerland, measuring road traffic noise has been a key point on the agenda for many years.
Until recently, measuring road traffic noise was a manual process, requiring city technicians to go to specific locations, set up sonometers, wait 15 minutes for a measurement, wrap up and move on to the next spot. With thousands of locations and technicians off on weekends and holidays — not to mention the specific meteorological constraints— it could take the city up to five years to cover the main roads of the State of Geneva. However, by then, noise levels may have already changed.
“The city would always be running behind since the corrective measures need to be taken faster if you want anything to change,” said Paul Royo.
With traditional sound level meters unable to provide real-time data over long periods (without special power supply) and also being too expensive for mass deployment, the city clearly needed an alternative solution.
Since 2016, the Service de l’air, du bruit et des rayonnements non-ionisants (SABRA) from the State of Geneva has been closely involved in the test and development of Sampols — OrbiWise’s high-performance, low-cost IoT-based solution for environmental noise management. The interface layer of the technology stack consists of a noise map that displays the road traffic noise all over the city. The collaboration between Orbiwise and SABRA has led to a deployment plan of about 200 sensors across the city of Geneva, which represents two sensors per city section. Once all sensors have been installed, the objective is to monitor the road traffic noise level in the long run (for the next 3-5 years).
“It feels like you suddenly have technicians everywhere with sound level meters everywhere,” said Royo. “We get instant measurements all across the city and are able to follow the noise levels 24 hours a day over several months.”
Each sensor precisely measures the average noise level, percentiles, battery voltage, relative temperature and humidity.
Connecting the two ends of the solution, while sending and storing data, is OrbiWAN, OrbiWise’s LoRaWAN network server. The data transfer is secure and encrypted end to end, and the intervals with which it is gathered can be customized — in this case every 15 minutes — but it can be from one minute to one hour depending on the project scope and timeline.
Both battery and sensor can be replaced with little impact as data is not sensor dependent, but location dependent. Since data transmission can be done in intervals of 15 minutes, the device’s battery is preserved longer and can last up to 1.5 years.
Overall, SABRA is greatly benefiting from deploying Sampols thanks to several factors. The low-cost sensors have a long battery lifetime and are easy to install, maintain and replace. Statistics can be accessed in real time with advanced data visualization features available for actively taking corrective measures to control any increased noise pollution. Application settings are customizable, offering automatic alert options, data importation from multiple sensors to create a rule and easy-to-view displays for following the sensors’ activity.
“At first, we thought that by placing some sensors we would be out of the woods,” said Royo, “but little did we know that the actual value was having a full end to end solution. A sensor is not enough. You need a complete solution including sensors, a communication network, a data storage platform, with a dashboard allowing data processing and visualization, plus maintenance tools.
OrbiWise is one of the rare companies providing a full noise sensors solution. It became critical for us to be able to have an analysis tool to actually extract useful information from the massive amount of data we were gaining.”