The California Senate has approved a bill intended to discourage the kind of sprawling suburbs and crawling traffic that have long characterized the communities where many of the state's 38 million people live. A goal of the bill, passed by the Senate over the weekend and approved in the state Assembly last week, is to ensure that increases in heat-trapping gases from passenger vehicles are kept to a minimum as the state is expected to grow by an estimated eight million people over the next two decades. The measure would loosely tie billions of dollars in state and federal transportation subsidies to cities' and counties' compliance with efforts to slow the inexorable increase in driving.