Well it looks like a certain anti-transit guy has crawled out from under the rock he has been under for awhile.
Of course his like usually use gross generalizations to try to make his point. Of course he mentions all trips along Interstate 15 but that includes both private and commercial vehicles plus vehicles traveling through the area.
What they don't say and never will is the percentage of traffic that rail is capturing in the corridor it specifically runs.
Also the highways are already an large integrated network, that rail has yet to achieve.