Using automatic vehicle location (AVL) data for evaluation of bus priority at traffic signals

Automatic Vehicle Location (AVL) systems are being used increasingly in public transport operations in towns and cities in the UK, providing applications including real time passenger information, bus fleet management and bus priority at traffic signals. AVL systems also usually provide a wealth of information on bus operational performance which can be used off-line for a range of analytical purposes, such as for improved scheduling or the identification of problem locations in the network. This paper discusses the use of AVL data for performance monitoring through a Case study of the iBus system in London. iBus is one of the largest bus-based AVL systems in the world, covering 8000 buses on some 700 bus routes, with 2500 bus stops showing real-time bus arrival times. One of its applications is bus priority at traffic signals, with facilities currently operational at some 2000 traffic signal installations. This paper concludes with a discussion of the limitations and statistical considerations needed with data of this sort as well as its advantages.