Aarhus, Denmark’s second largest city, is using Bluetooth sensors to gain better insights on congestion and to optimize traffic light signals.
Aarhus is a city with around 230 intersections regulated by traffic lights. Naturally, if one of these installations is not working, it affects traffic flows throughout the city.
Many of the city’s traffic light installations do have built-in alarm systems, which can warn city officials when they experience a mechanical error or if a bulb has gone, but they are unable to report on the impact of such malfunctions, which often result in congestion.
To tackle this problem, the city is using a system of Bluetooth sensors known as BlipTrack from tracking and sensor technology company Blip Systems.
These Bluetooth sensors are placed on the entire road network, including adjacent highways, to provide the city with real-time and historic traffic information. This data includes driving times, speed, dwell times and flows throughout the city.
The real-time data provides information on current road usage and congestion, allowing officials to share traffic information with road users via signs, while historic data is used to detect driving time anomalies, such as when drivers are affected by roadworks.
If the system detects driving times in one area deviating from the norm, it will raise a flag. Using both data sets, the city has a clear overview of the current problem combined with historic issues, and can provide a countermeasure. This is what Blip Systems calls alarm visualization.
Aarhus benefits from smart city systems
“The benefits we have gained from the solution since implementation are very significant,” said Asbjørn Halskov-Sørensen, ITS project manager at Aarhus Municipality.
“We now discover errors and irregularities that we would not have a chance to see otherwise. In addition, it is extremely educational and easy accessible to study how the incidents of various kinds influence the road network.”
City officials say the system is indispensable for the optimization of traffic. To date. it has picked up numerous issues such as errors caused by incorrect activation of traffic light programs, defective surveillance systems, or human error, such as forgetting to switch back to the normal program following maintenance.
“BlipTrack data is generally used for much more than just being able to measure the effect of signal optimization and roadwork/construction projects, but this is clearly an important part of its application”, said Halskov-Sørensen.
“Ultimately, the data contributes to an improved economy and a better environment through reduced driving times and fuel consumption, and thus reductions in greenhouse gas emissions from vehicles.”
Aarhus has been using the system for several years, and, with full access to this raw traffic data, it now plans to combine the BlipTrack system with existing surveillance systems. Supposedly, this will enable the city to qualify the individual system’s alarms to an even greater extent.
BlipTrack is also used in cities in the UK, Canada, Thailand and Switzerland among others. It is also used in more than 25 international airports, including the UK’s Birmingham Airport.