Faced with significant infrastructure deficits, U.S. governments at all levels are increasingly considering the use of public-private partnership (PPP) to leverage private finance to support public infrastructure development. This study focuses on PPP tolling in highway development and seeks to explain the determinants for adopting this innovation, using data on toll road activities in the United States during 1985-2010. The results show that the probability of adopting PPP in highway tolling projects is significantly affected by traffic demands and fiscal pressures, liberal political ideology and administrative inertia, state wealth, state PPP legislation, and earlier experiences of PPP adoption in the state and elsewhere.