these raw materials will have secondary effects on emissions from stationary sources, energy usage, and other parameters in a wide variety of industrial operations. To determine the overall societal effects, the direct and indirect effects of these changes on the overall industrial system will have to be analyzed.

A large number of technologies must be considered to reach a goal as ambitious as Goal 3. During the first four years of the PNGV program, both the USCAR partners and the government research managers examined hundreds of technologies and ideas that might have contributed to the success of the program. The 2004 deadline for completing production-ready prototypes, together with reasonable limits on available resources, dictated that selections of the most promising technologies be made during 1997. As the PNGV program has matured, however, it has become evident that some promising technologies will not be ready for the construction of a production prototype car in 2004. This suggests that the technology selection process should recognize some technical approaches as near-term candidates, some as longer-term possibilities, and some as not likely to be used in passenger cars in the foreseeable future, although they may be deserving of continued R&D at some level.

The PNGV reached its initial technology selection process milestone on schedule, and the USCAR partners can now continue with the design and construction of concept vehicles. Meeting the PNGV goals required that they adhere to this demanding schedule, and they have accomplished this task. The committee notes and commends their progress. The vehicle criteria in Table 4-2 were the basis for deciding which technologies will be applicable for concept vehicles.

Although the technology selection has been completed, the process PNGV