A bill toughening Minnesotas drunk-driving law has been moving through the Minnesota House. 1998 saw an increase in alcohol-related highway deaths, and the bills proponents say lowering the blood-alcohol limit from point-one-oh to point-oh-eight would save lives. State highway patrol officers, meanwhile, say drunk drivers are one of their most persistent challenges. The patrol spent last week training new recruits in the art and craft of detecting drunks.