Public Funding for RBM Traffic Solutions Ltd

The project will utilise evolutionary artificial intelligence to address the problem of optimising prices and signals in road transport networks. The ability to set road prices and signal control settings are traffic management tools which can be utilised to optimise transport flows in the network. However, making changes to prices and signals will impact people's travel decisions, since individuals are motivated to minimise their own travel cost (which includes travel time as well as monetary cost). This means that travellers will swap to less costly routes should they be available. This makes the problem of optimising the control variables (for example the prices and signals) nonlinear and difficult to solve. The degree to which the traffic flows in a network are optimised needs to be assessed with respect to certain objectives, such as for example minimising queues or reducing pollution, and the use of an objective function can be used to precisely quantify the degree to which the objectives are met. A genetic algorithm is an artificial intelligence technique which uses a process of natural selection to find solutions to a problem. It is based on the idea of survival of the fittest; the fittest individuals (that is, the most promising solutions to the problem) being those most likely to survive and reproduce. This reproduction involves selection of 'chromosomes' from the parents in a random way, so that the offspring is a mix of the two 'parent' solutions. When repeated, this process generally leads to improving solutions over time. The performance of a particular solution (i.e. the particular price and signal settings) will be evaluated by adopting these control settings within a road traffic network model and adjusting flows (towards less costly routes) until the user equilibrium flows are found (which occurs when there is no more route swapping). The value of the objective function (which for example could be the sum of all the lengths of the queues in the network) based on these user equilibrium flows gives an indication of the performance of the solution. The road traffic network model utilised for this purpose will be the computer simulation model which is currently under ongoing development by RBM Traffic Solutions Ltd. This model can quickly find the user equilibrium flows, which makes it ideal for the large succession of model runs which will be needed when implementing the genetic algorithm optimisation approach.