CONCLUSION: Policies designed to accelerate the penetration of HFCVs into the U.S. vehicle market will be required to exploit the long-term potential of HFCVs. The committee concluded that these policies must be durable over the transition time frame but should be structured so that they are tied to technology and market progress, with any subsidies phased out over time. Such policies are likely to deliver significant long-term reductions in U.S. oil demand, but additional policies limiting greenhouse gas emissions will be required in order to also reduce CO₂ emissions significantly.

If policy makers decide to push the market penetration of HFCVs, these policies should be seen as a complement to (not a substitute for) broader measures to reduce greenhouse gases and oil use. However, the committee believes that HFCV-push policies would have to be designed very carefully if they are to be effective. Incentives must be substantial, durable, and coordinated with measures to encourage the development of a hydrogen fuel distribution infrastructure and continued basic research on vehicle design. Moreover, it is not entirely clear whether a price-based (subsidy) approach or a quantity-based (quota) approach to promoting vehicle sales is preferable; both approaches have pros and cons. A mix of the two approaches, however, might afford the most effective policy to achieve the maximum practicable deployment of fuel cell vehicles in the time frame examined in this study.