Efficiency vs. correctness of a travel information system

Most of the general public support the British government's aim of reducing congestion and pollution and are in favour of positive measures to improve public transport. To ensure the continuation of recent successes in reversing years of decline in public transport use, good quality service information and access are of paramount importance. This paper focuses on the issue of flexible provision of information about public transport and assistance with planning travel. Included in this is the consideration of travel time, possible delays and inconvenience of making connections. This paper also describes the infrastructure that is currently being developed at The Nottingham Trent University to facilitate multi-modal travel throughout the city of Nottingham, with particular reference to buses and trams. Due to the very large number of links and nodes inherent to public transport networks, and to the decision-making capabilities of the traveller, it is necessary to prune the search space of the algorithm. Such pr