A major obstacle confronting the widespread acceptance of natural gas vehicles (NGV) is their substantial cost premium over conventionally fueled vehicles. Currently, as much as 70 percent of the cost premium can be related to on-board storage costs. Market growth is dependent on making NGVs more affordable and storage costs are the primary element. This report identifies and assesses the market potential of compressed natural gas storage technologies that will reduce the cost of on-board storage into the range of $0.35 to $0.50 per standard cubic foot of gas while also reducing weight. Based on weight, cost, and safety evaluations, a number of cylinder optimization options were identified with the most potential to reduce cylinder cost and weight while maintaining a high level of safety. These options included high strength steel cylinders, high strength aluminum cylinders, all-steel cylinders from tube stock, and low-cost carbon fiber.