Commuters in taxi cabs across the UK cities of London, Edinburgh, Glasgow, Manchester and Birmingham will soon receive context-relevant messages as they travel. A total of 4,000 Bluetooth Low Energy (BLE) beacons are being installed in taxis by mobile proximity marketing provider Proxama and taxi advertising provider Ubiquitous. Proxama also partnered out-of-home media owner Exterion to roll out beacons across public transport services.