CURRENT RESEARCH
Only limited research is currently taking place in PCP to improve the
system. Four current or recent research projects are known. One is a
project completed recently at the University of Minnesota, sponsored
by the Minnesota Department of Transportation (7). This study
investigated the possible use of large conduits or tunnels of diameter
greater than 3 m placed under a highway. The capsules are selfpropelled
vehicles carrying their own electric motors. Such a system
is more of the nature of underground electric trains rather than PCP,