Abstract
This article briefly describes transportation knowledge networks, from their conception as presented in Transportation Research Board Special Report 284, "Transportation Knowledge Networks: A Management Strategy for the 21st Century" (2006), to the plan for their implementation developed by National Cooperative Highway Research Program (NCHRP) Project 20-75, Implementing a Transportation Knowledge Network. With the support and guidance ofthe National Transportation Library and transportation librarians, three regional transportation knowledge networks have been established. However, funds are needed to bring more information sources into the network and to improve user awareness and access.