Edinburgh Napier University

  The routing of employees who provide services such as home health or social care is a complex problem. When sending an employee between two addresses , there may exist more than one travel option, e.g. public transport or car. In this paper we examine the optimisation of travel plans, supporting the provision of health and social services, with respect to objectives of travel times and estimated CO 2 produced. We include modal choice, either car or public transport as a decision variable. Car travel is normally quicker, but has a higher CO 2 cost, whereas public transport may have longer journey times, but produces less CO 2. We examine a set of problems involving real city and transport network data based in the UK cities of Edinburgh and London. We show that a multi-objective Evolutionary Algorithm can produces Pareto sets of solutions that allow a trade off between CO 2 and travel time through the use of the decision variable.