TRANSYT is an international product, used by hundreds of consultancies and local authorities around the world. It is an off-line computer program for designing, modelling and studying everything from individual isolated junctions to large complex networks. TRANSYT can quickly assess individual junction performance and also produces optimum fixed-time co-ordinated traffic signal timings in any network of roads for which traffic flows are known. Its use around the world reflects the product's international appropriateness and flexibility as a design and network optimisation tool. TRANSYT is built upon extensive quality research over many years and is a powerful, useful and time-saving tool in the Traffic Engineer’s arsenal.