The transportation tax approved by Hillsborough County voters in November appears enticing to several candidates for Tampa mayor who are offering their own spending plans for improving roads and transit. But while the next mayor will play a major role in shaping Tampa's transportation future, some of the biggest decisions on the splashiest projects will be outside the city's control. That’s a reminder that the next mayor must work effectively with other partners on this regional issue, a reality that went unacknowledged in this week’s first major mayoral debate.Ed Turanchik released a sweeping proposal last week to improve roads and pedestrian safety, expand mass transit and connect Tampa and St. Petersburg with ferries. The plan is no surprise, coming from a former Hillsborough County commissioner who has made transportation a pet project for decades, and it included components that have formed the backbone of every major transportation plan for Tampa in recent times.Another mayoral candidate, Tampa City Council member Harry Cohen, released his transportation plan in November. It also calls for expanding mass transit and improving connections between neighborhoods and major employment centers. Both candidates also envision a downtown transit hub, another longtime planning mainstay.But the big-ticket projects being considered - from express bus service to a connector between downtown, the University of South Florida and the airport, for starters - would fall to other agencies, from HART, the county's mass transit provider, to the state and federal governments. The one-cent transportation sales tax would provide Tampa an additional $30 million per year, enough to accelerate road paving and other routine maintenance and to subsidize some mass transit in the urban core. HART, by comparison, stands to receive an additional $136 million per year, more than four times the city's share. And HART - not the city - would be the agency attracting any state and federal matching funds for start-up costs and operations of any expanded mass transit system.Cohen has been clear that his plan for Tampa involves major commitments by HART and other agencies. And the mayor of Tampa, the region's biggest city, would obviously carry significant sway, given Tampa's population and economy, its membership in HART and other transit agencies and its links to federal and state support for Tampa International Airport and Port Tampa Bay. The new mayor will need a solid working relationship far beyond City Hall and a vision for transportation that earns the confidence of the city's many long-term partners.The transportation tax is a gift to the mayoral candidates in the run-up to the March election. But voters need more than a wish list. Only Cohen and Turanchik offered any specifics on transportation in Wednesday's televised debate. Every candidate needs to lay out their priorities, funding plans and timetables.How would they use transportation to make the neighborhoods safer and more vibrant? How would they better connect residents to jobs and major destinations? How would they work with area mayors and other leaders to improve mobility throughout Tampa Bay? With the debates under way the mayoral election less than two months away, it's time for voters to look beyond the platitudes for candidates with a coherent message and an achievable vision. That will be key in electing a mayor who can build on Hillsborough's transportation vote for the good of the entire region.