LA Mayor Eric Garcetti, City Councilman Mike Bonin and County Supervisor Mark Ridley-Thomas have all said at some point this year that the Expo light-rail line from downtown to the Westside would "decrease traffic" and "reduce congestion." They're elected officials promoting a $930 million project. Now some data is coming in, and although it turns out that gridlock remains on streets and freeways, ridership is a pleasant surprise: it's already what was expected for 2025. Professor Genevieve Giuliano is director of the METRANS Transportation Center at USC.