While more than 70 utilities in the U.S. have offered voluntary RTP tariffs on either a pilot or permanent basis, most have operated in relative obscurity. To bring this broad base of conducted survey of 43 voluntary RTP tariffs offered in 2003. The survey involved telephone interviews with RTP program managers and other utility staff, as well as a review of regulatory documents, tariff sheets, program evaluations, and other publicly available sources. Based on this review of RTP program experience, we identify key trends related to:

• utilities' motivations for implementing RTP,
• evolution of RTP tariff design,
• program participation,
• participant price response, and
• program outlook.

We draw from these findings to discuss implications for policymakers that are currently considering voluntary RTP as a strategy for developing price responsive demand.