The PPP transit market in the U.S. is far behind Canada’s, but design-build and traditional design-bid-build projects are lining up quickly at TIFIA’s loan window.  LA Metro was granted a $546-million loan last year to build its $1.5-billion Crenshaw LRT line. Four more transit megaprojects worth about $20 billion are in line for a TIFIA loan from U.S. DOT, or soon will be. Half of them are for Los Angeles Metro projects, which receive strong support from a regional sales tax and from U.S. Sen. Barbara Boxer (D-Calif.), who chairs the Senate Environment and Public Works Committee: