The Three Feet for Safety Act, a state law passed by the Legislature and signed into law by Gov. Jerry Brown, takes effect Tuesday - in time to help make bike riding safe during the traditional back-to-school surge in two-wheel commuting. Drivers have always been required to pass bicyclists on the left and to allow a safe distance between the motor vehicle and the bike. Impatient drivers who squeeze past bike riders at a closer distance are subject to fines of $35 plus court costs, which increase the cost to $237. According to the California Highway Patrol, 153 bicyclists were killed in collisions with motor vehicles in the state in 2012, a 7 percent increase from 2011. Some drivers have asked what happens if a bicyclist swerves toward them or tries to squeeze through slow-moving traffic between cars, making it difficult or impossible to stay 3 feet away.