TAMPA — In 2010, Hillsborough voters soundly rejected a 1 cent sales tax hike backed by their elected leaders to raise billions of dollars for roads, bus expansion and light rail.

In 2016, county commissioners helped develop a new transportation plan minus the light rail but pulled the plug on a referendum that would have let voters decide.

Now, a citizens group has put county commissioners on notice that a new effort is under way to get a sales tax hike on the November ballot — and this time, their approval won't be necessary.

The group has its own heavy hitters. Commissioners learned of the plan from supporter Jeff Vinik, owner of the Tampa Bay Lightning and the driving force behind a $3 billion entertainment district around Amalie Arena.

All for Transportation, as the group is called, must collect 49,000 signatures in the next six weeks to get an initiative on the ballot. The measure would ask voters to approve a one penny county sales tax hike, from seven cents on the dollar to eight cents, for a 30-year period beginning in 2019.

Forty-five percent of the money raised would go to the Hillsborough Area Regional Transit to improve bus service and pay for other mass transit. The remainder would go to Hillsborough County, Tampa, Temple Terrace and Plant City for road and bridge improvements, pothole repair, sidewalks, bike lanes and projects to ease congestion.

If approved by voters, the tax would raise about $280 million per year.

Vinik phoned several county commissioners earlier this week to give them advance notice of the plan.

"Like many in our community, he believes our county needs to vastly improve its transportation network if we are to realize our full potential in the decades ahead," Vinik spokesman Bill Wickett said in a email. "He looks forward to seeing this effort take shape."

A rarely used process known as charter amendment by petition would allow All for Transportation to bypass the seven-member County Commission with its fiscally conservative Republican majority and make its case straight to voters.

The group has formed a political committee to raise funds for a petition drive and campaign. Today, it plans to file ballot language and a charter amendment petition with the Hillsborough County Supervisor of Elections.

Leading the effort is Tyler Hudson, a Tampa attorney and Tampa Heights resident who worked as deputy field director in Florida for the Barack Obama 2008 campaign. Other members of the group include University of South Florida Trustee Nancy Watkins and her husband, Robert Watkins, both prominent GOP campaign donors.

"When you talk about 600,000 new people moving here in the next 30 years, you're in a situation where we're not going to be able to move," Hudson said. "We think this is a timely solution to a really urgent problem that affects people in every corner of the county."

The initiative has the support of Tampa Mayor Bob Buckhorn, who said the region's transportation system lags behind other metropolitan communities. Voters in the city favored the failed 2016 Go Hillsborough transportation plan but it was defeated countywide.

"I couldn't be happier to hear citizens are demanding action," Buckhorn said. "Bring me a petition, I'm ready to sign."

Officials from The Greater Tampa Chamber of Commerce said they need more details but are "excited to see the energy behind this grassroots effort to address transportation issues in the region."

If approved, the tax would go to projects identified in a long-range transportation plan developed by the Metropolitan Planning Organization, a transportation policy-making board made up of elected leaders from Hillsborough County, the School Board, Port Tampa Bay, Tampa International Airport and all three municipalities.

Tyler said if the group comes up with enough signatures by July 29, more details about what voters get for their money would emerge during the campaign to pass the plan.

Opponents would likely mount their own spirited campaigns, as they did with the 2010 and 2016 Hillsborough transportation plans and the failed 2014 Greenlight Pinellas plan.

RELATED: Hillsborough commission rejects transportation sales tax 4-3

Hillsborough Tea Party co-founder Sharon Calvert, who worked against Go Hillsborough in 2016, questioned whether All for Transportation had explored other funding options.

"Why is it always a tax hike?" she said. "A 30 year tax is billions not millions."

The All for Transportation proposal would include an oversight committee made up of citizens to ensure the money is spent as voters intended, Hudson said.

"They're going to audit the funds and have the ability to withhold the funds," he said. "It will be an independent committee with teeth."

The vote on the plan would be held in an off-year election when turnout overall is typically lower but when Republican turnout is proportionately higher. Opposition to tax hikes is a central tenet of the GOP.

Just over 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 the presidency of Donald Trump.

Commissioner Al Higginbotham was one of four Republican commissioners who voted against Go Hillsborough. He pledged in 2006 never to raise taxes, a promise he later felt restricted him.

"Transportation certainly needs to be addressed," Higginbotham said Thursday. "Depending on how the language is drafted, it could be a very good thing for Hillsborough County."

Contact Christopher O'Donnell at codonnell@tampabay.com or (813) 226-3446. Follow @codonnell_Times.