The city of Calgary, Alberta is using Bluetooth technology to monitor traffic conditions and alert commuters of any delays along their route in realtime. By anonymously tapping into the unique identifier codes found in all Bluetooth-compatible devices — smartphones, tablets, hands-free headsets, etc. — the city's Travel Time Information System collects the whereabouts of drivers at 15 points along the Deerfoot Trail, a major six-lane freeway in Calgary. This data is sent to central hub where workers can dispatched messages to a number of roadside displays that can warn commuters of impending delays and urge them to seek alternate routes.
The city ran trials for the system in 2010 and has been working to improve its reliability since; advancements have allowed them to largely exclude signals from nearby pedestrians and drivers on other roads, for instance. Crowdsourced GPS apps like Waze (and the now-defunct Dash hardware before it) have similarly proven popular for their ability to offer up accurate traffic data.