Federal authorities could force Caltrans to kick hybrid vehicles out of congested carpool lanes or require drivers of non-hybrids to pick up an extra passenger to gain admission to overused lanes. And that could help unclog carpool lanes in the Bay Area, most of which have become commute-hour slogs, according to a Caltrans report compiled after more than 50,000 hybrids were given access to the lanes. The report found that carpool lanes on Interstates 80 and 880 and Highways 101, 4, 85 and 237 have gone from being relatively free-flowing routes in spring 2005 to stop-and-go congestion this past spring....