[Excerpt] Car rental companies offer customers various combinations of car types, rental periods, and pickup and return locations, as well as insurance and refueling options. Hertz developed its yield management system (YMS) to help decide the availability of these combinations of products over time. The YMS integrates information management technology, sophisticated operations research techniques, and information from existing Hertz decision support models that solve the closely-related problems of pricing, fleet planning, and fleet deployment.