The People's Transportation Plan (PTP) was grandly designed to solve Miami's upcoming date with permanent gridlock. The shiny lure that voters went for was the promise that a half-penny sales tax would buy them an expanded and improved mass-transit system. Nowthey're told the tax was in reality designed to win matching state and federal funds, not to actually build a new system -- never mind the ballot language. According to a county study, absent these outside funds (and none of them are guaranteed), the PTP could literally bankrupt the transportation system. In addition, county commissioners are maneuvering to strip powers from the PTP's mandated watchdog group, the Citizens' Independent Transportation Trust. If county officials bit off more than they could chew with the PTP, perhaps they should consider the South Beach diet before asking taxpayers for more dough to cover their gluttony.