Headway-based bus priority in London using AVL: first results

Bus priority is being widely implemented across many UTC areas in London, following successful field trials in the EC-funded projects PROMPT and INCOME. Installation has now been completed at over 100 junctions, with full evaluations being undertaken in each case. The remaining roll-out programme includes over 500 additional junctions. This roll-out has initially been based on the existing technology of bus transponders and inductive loop technology. However, the committed London-wide implementation of automatic vehicle location (AVL) technology for fleet management and passenger information at bus stops offers the potential to use new technology and more sophisticated control for bus priority. In particular, the real-time bus location information, provided by AVL, enables the level of priority provided for each bus to be tailored to its needs. The possibility of using AVL to support bus priority at traffic signals in London was raised in the early 1990s, when the first AVL-based COUNTDOWN trials were commissioned. A feasibility study undertaken for London Transport Buses (LTB) by the Transportation Research Group (TRG) at Southampton University indicated potential benefits and likely cost-effectiveness. A method of selective priority for buses, that differentiates between buses based on their headways, was developed and evaluated by TRG using simulation. This method was integrated into the bus priority system, and known as the Headway Regularity Algorithm. System commissioning on a section of the Uxbridge Road was undertaken in 1998/99, leading to technical trials and the first live trials in June/July 1999. The paper summarises this research, development and installation process before describing the first results of the trials in more detail