ST. PETERSBURG — Mayor Rick Kriseman is keenly interested in the latest attempt to pass a transportation sales tax in Hillsborough County.All for Transportation is campaigning to convince Hillsborough voters to approve a 1-cent sales tax increase to fund mass transit, road projects and bike and pedestrian improvements.TIMES ANALYSIS: Tampa Bay has one of the worst transportation systems in America. Here's why.If the referendum passes in Hillsborough, then the mayor wonders if Pinellas should mount a similar referendum on his side of the bay in 2020 — or at least St. Petersburg, should the Legislature ever allow cities to hold their own referendums."If it passes there, I think it helps us talk about it here again," Kriseman said. "The more we have these little victories here and there and show there are ways of using transit other than your car, the easier it is to take that next step."Of course, that would mean overcoming the stinging defeat of Greenlight Pinellas in 2014, the transportation referendum rejected by 62 percent of voters that year. That plan would have expanded the county's bus service and built a 24-mile light rail system connecting St. Petersburg and Clearwater.Other transit advocates, like Pinellas County Commissioner Janet Long, aren't convinced another referendum attempt is the way to go. While she said the county's list of transportation needs is long, she would like to see her fellow leaders explore other funding options before asking voters to raise their own taxes."Before we go out and ask voters for any kind of a referendum in Pinellas, it's really, really important that we look at the way we are already using our current revenue," Long said. "And figure out if there isn't a better, more effective and more efficient way to fund some of these issues we have with transportation."RELATED: Petition succeeds, Hillsborough voters set to decide on sales tax hike for transportationPinellas County Commission chair Ken Welch agreed with Long that the county should continue to explore state and federal grants, along with existing local funding options, before looking at a tax increase.“I think the time for a referendum will come again, but I don’t think it’s on a near horizon for us,” Welch said. “Some form of increasing our local support for transportation has to happen, but for the near term I believe we’re going to look to local sources and partnerships, like the gas tax, bed tax and Penny for Pinellas.”While all of those options could chip away at the county's long list of transportation needs, nothing comes close to matching what a sales tax can raise, said Pinellas Suncoast Transit Authority executive director Brad Miller.For example, he said a gas tax could raise about $17-19 million a year. A tax on tourism development could generate another $10 million. But a one-cent sales tax could raise more than $100 or $200 million annually, depending on the county and year. That's about 10 times the amount other funding sources can generate, Miller said."I don't know that trying to cobble together a whole lot of different options is going to get us enough to get where we need to go," Kriseman said. "Whereas with a sales tax, clearly it's going to generate a whole lot more revenue than the others."Ideally, Kriseman would like to see St. Petersburg put its own transportation sales tax on the ballot. But the state Legislature has repeatedly denied cities the ability to do so. Kriseman and other mayors will be lobbying the state again next session.The latest Hillsborough effort comes after two failed attempts to pass a transportation tax in that county. A 2010 referendum was soundly defeated by voters. And in 2016, the Hillsborough County Commission wouldn't even let voters decide for themselves.Instead, commissioners voted 4-3 not to put the Go Hillsborough referendum on the ballot that year — a presidential election year that saw Hillsborough go blue.FROM 2016: Hillsborough commission rejects transportation sales tax 4-3File photo of Rick Kriseman, who spoke at a press conference criticizing Ron DeSantis for his stance on health care Tuesday, Sept. 25. [SCOTT KEELER | Times]Kriseman, who has pushed for a variety of transit projects throughout his time in office, told the Tampa Bay Times last week that he was proud of the recent transportation initiatives in Pinellas: bringing back the Cross Bay Ferry; seeking local, state and federal funding for the Central Avenue Bus Rapid Transit project to link downtown to the beaches; and expanding the downtown Looper. Still, far more needs to be done."It's a good start," the mayor said, "but we sure have a lot more work to do when it comes to transit."RELATED: Could Trump starve a Tampa Bay transit project of federal funds?Long agreed, praising county officials for finding creative ways to pay for new projects. But she said what they have accomplished pales in comparison to the county's massive transportation needs."We're plugging a hole little by little, but we're not addressing the big needs or taking hundreds of thousands of cars off the road," Long said. "It takes a lot more than what we've been able to cobble together."And while Welch doesn't see an immediate need for a sales tax increase to fund transportation needs, he acknowledged that conversation must happen at some point, particularly when it comes to expanding the bus system. The Pinellas bus agency is grossly underfunded compared to similar sized agencies nationwide.“If we want to take those next steps to get a bus system that’s funded adequately, to get some sort of premium transit, be it (bus rapid transit) or rail, to connect with that high speed rail line to Orlando,” Welch said, “then we’re going to have additional funding at some point down the line.”That's why, despite putting together several transit initiatives without raising taxes, Kriseman is keeping a close watch on the fate of Hillsborough's referendum.Should it pass, Hillsborough's sales tax would increase from seven cents on the dollar to eight cents for a 30-year period starting in 2019. About 45 percent of the money raised from the new tax would go to the Hillsborough Area Regional Transit authority to improve bus service and pay for a new form of mass transit.The rest would go toward road and bridge improvements; fixing potholes and sidewalks; building more bike lanes and other projects to ease congestion.RELATED: Needs are great, but will Hillsborough voters go for two tax hikes at once?Complicating matters in Hillsborough is another referendum: The School Board voted to put a 10-year, half-cent sales tax on the same Nov. 6 ballot. Will voters approve both tax increases, raising the sales tax to 8½ cents on the dollar? Or will one sink the other?And were Hillsborough to start building a mass transit system, then Pinellas voters would go to the polls knowing that they could choose to build a system that could one day bridge the bay.Contact Caitlin Johnston at [email protected] or (727) 893-8779. Follow @cljohnst.