TAMPA — The group behind a sales tax transportation initiative used hundreds of volunteers and spent at least $550,000 on a petition-gathering firm in a frantic six-week dash to qualify for the Nov. 6 General Election ballot.That may have been the easy part.Now All for Transportation must sell the tax hike to voters who overwhelmingly shot down a similar proposal in 2010 and watched Pinellas voters do the same in 2014.So why will this time be any different?The group is betting that a grass-roots campaign built on a petition of almost 77,000 signatures has more chance of success than one spearheaded by a local government or bus agency. Their plan does not commit the county to building a train service, which was a rallying point for opponents like "No Tax for Tracks."And unlike the two past referendums, this one will be conducted in an up economy and at a time when Florida is pushing ahead with major transportation projects such as a high-speed rail link between Tampa and Orlando.Stephen Neely, a professor in the University of South Florida’s School of Public Affairs, sees grounds for supporters of the initiative to be optimistic."Because the economy is strong, voters are more likely to accept marginal tax increases if the initiative is seen as legitimate and beneficial," he said in an email. "If local business leaders are able to effectively present it as being a net positive for economic development in Hillsborough County, they will likely be able to succeed."All for Transportation’s plan is not a long list of proposed transportation projects. Instead, it commits the $280 million a year the tax would raise to priorities adopted in a long-range transportation plan developed four years ago by the Hillsborough County Metropolitan Planning Organization.And it makes roads and not buses the highest priority. A majority of the money — 55 percent — would go to Hillsborough’s four local governments — Tampa, Temple Terrace, Plant City and Hillsborough County — to spend on road improvements.The Hillsborough Area Regional Transit authority would get the remaining 45 percent of the tax proceeds. Most of that would go toward expanding bus service while about one-third would be spent on a transit system with its own right-of-way linking the University of South Florida, downtown Tampa and West Shore. That could be bus rapid transit, light rail or traditional rail using existing CSX tracks.The group plans to reach out to residents with examples of how the tax would mean more frequent resurfacing and repair of potholes, more "intelligent" traffic signals that can change cycles to reduce congestion, improved intersections and better bus service in their neighborhood."It will be a tailored message to individual communities," said Tyler Hudson, All for Transportation’s chairman. "We want to make sure that everyone in Hillsborough County gets something from this plan."But a lack of specifics could make it a tougher sell. Past elections have shown that initiatives are more likely to gain public support if the funding and future expenditures are clearly spelled out, Neely said."Ambiguous or ‘general’ funding requests are more likely to be denied," he said.As a Pinellas County commissioner and then-chairman of the Pinellas Suncoast Transit Authority board, Ken Welch helped spearhead the doomed Greenlight Pinellas campaign in 2014.The $2.2 billion plan included a $1.6 billion, 24-mile light rail service from St. Petersburg to Clearwater that opponents derided as a train that no one would ride. The referendum lost badly, going down by a margin of almost 24 percentage points"That sucked all of the wind out of the room," Welch said of the light-rail proposal. "Everything was focused on that."But the transportation landscape is much changed since 2014, Welch said, pointing to a proposed 41-mile Bus Rapid Transit system between Wesley Chapel and St. Petersburg and another BRT planned to link St. Petersburg to Pinellas beaches along Central Avenue. That’s in addition to the high-speed rail proposed to link Tampa and Orlando."Folks can now see a blueprint for how we connect our major activity centers," he said. "But each taxpayer will have to see value when they mark that ballot. That has always been the challenge."All for Transportation opted to take their plan to voters in an off-year election when turnout overall is typically lower and Republican turnout is proportionately higher. Opposition to tax hikes is a central tenet of the GOP.More than 60 percent of registered Republicans in Hillsborough voted in the last mid-term election in 2014 compared to 49 percent of Democrats. But some political observers are predicting a higher Democratic turnout this year in a so-called Blue Wave of opposition to Republican President Donald Trump. And high-profile ballot initiatives like this one can drive up voter turnout by as much as 5 percent, especially when preceded by a petition effort, Neely said.Still, he expects support will fall along traditional party lines with most Republicans opposing the tax increase. "The outcome will hinge largely on voter turnout and enthusiasm surrounding the general midterm elections," Neely said.Contact Christopher O’Donnell at [email protected] or (813) 226-3446. Follow @codonnell_Times.