Aarhus, Denmark's second-largest city with around 230 intersections regulated by traffic lights, has been using BlipTrack Bluetooth sensors for several years to collect traffic information, based on the movement of road users' Bluetooth devices.
The sensors, placed on the entire road network including adjacent highways, provide the city with both real-time and historical traffic information, including driving times, speed, dwell times and flow.
Besides the benefits of real-time reporting, which enables the city to gain in-depth insight and understanding of current road density, flow and formation of queues, and share traffic information with road users on signs, the historical data is now being used to detect driving time anomalies.
This means that the city can pinpoint road sections and intersections where driving times deviate from the norm as a result of construction, incidents, roadwork, faulty traffic lights and other factors.
The data provides a comparison of current vs typical driving times, minute-by-minute throughout the day. The typical driving times, which are continuously updated, are also based on various type of days (weekdays, weekend, vacation season or not) and time of day.
Photo: Blip Systems
Information can be displayed in various ways; for example, over time and for each road section, based on intersection errors, or the impact of a major traffic accident. It can show the scattering effect that can cause both a deterioration and improvement of driving times - depending on what alternative routes motorists choose to take advantage of - or if road users are prevented from reaching parts of roads.
“The benefits we have gained from the solution since implementation are very significant. 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,” Asbjørn Halskov-Sørensen, ITS Project Manager at Aarhus Municipality, said in a press statement.
While the many traffic light junctions in Aarhus do have built-in alarm systems that warn about mechanical errors, these alarm systems are "dumb", unable to report on the consequences of the errors or traffic regulation programs.
The alarm systems cannot see whether an error is causing queue formation or longer driving times for the road users, and they cannot see whether the amount of traffic has changed over time, calling for a change to the traffic light system program. This means, for example, that sudden or continuous traffic increase could result in major gridlock, without warning.
To meet this challenge, Aarhus opted to turn the problem on its head and to see the traffic flow from road users' perspective. Now, issues are detected, enabling the city to ensure that traffic lights are working correctly and programmed optimally.
Photo: Blip Systems
“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.”
BlipTrack also is successfully employed in optimization efforts in more than 25 international airports, including Schiphol Airport in Amsterdam, JFK Airport in New York, Copenhagen, Oslo, Manchester, Dublin, Brussels, Geneva, San Diego, Keflavik and Edinburgh, says the company in a press statement.