BRANDON — The snarl of traffic starts early on Bloomingdale Avenue, brake lights inching west in a blur toward Interstate 75.

Almost 50,000 vehicles travel the four-lane road every day. Congestion is so bad that traffic engineers give it an F, the lowest possible grade.

There are plans for improvements — more turn lanes, pedestrian crossings, bike lanes. A bus route could help take some cars off the road and a two-lane bridge spanning I-75 could be widened.

But no one has come up with the money for any of this work, or for hundreds of other transportation fixes across Hillsborough County that now add up to some $9 billion.

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The latest stab at an answer comes from a citizens group backed by business leaders grown weary of inaction by government leaders. They've succeeded in landing a proposal on the Nov. 6 general election ballot to raise the sales tax by one cent on the dollar and bring in $276 million a year for road and transit projects.

If approved, local government agencies say the money could be used to:

• Resurface Tampa's roads every 25 years instead of every 75 years.

• Build a mass-transit system linking the university area, downtown Tampa and the Westshore-Tampa International Airport area.

• Round out a planned network of 400 miles of bike and pedestrian trails.

• Add 10 new routes, 150 new buses and increase the frequency of at least four bus routes to every 15 minutes.

• Plug roughly 500 miles of sidewalk gaps on roads in unincorporated Hillsborough.

• Make intersection improvements throughout the county, including the addition of intelligent traffic signals that adjust to real-time traffic flow.

Other priorities include adding bus and express-bus routes in south Hillsborough, the restoration of bus routes that were cut by the cash-strapped Hillsborough Area Regional Transit authority, and more crosswalks and street lighting to make roads safer.

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"We are always having to prioritize and explain to people why we can't do something now or at all," said Jean Duncan, Tampa's transportation and stormwater director. "It would be amazing to our residents and even people traveling through our area how many great changes could be made to our transportation network."

The changes don't come cheap.

Estimates from a long-range plan by the Hillsborough Metropolitan Planning Organization say the 30-year tax would raise about $8 billion in its first two decades. The plan, developed in 2014, does not provide estimates for the final 10 years of the tax.

For a household with an income that's average for the county, around $55,000, the proposal would mean an extra $120 per year in taxes, according to a sales tax calculator developed by the Internal Revenue Service. Out-of-county commuters, visitors and tourists would also pay when they spend in Hillsborough.

The citizens group, All for Transportation, landed the plan on the ballot by collecting 77,000 signatures countywide. Most of the money — 54 percent — would be earmarked for roads, sidewalks and trails. About 45 percent would go to bus and transit.

But don't expect everything to be fixed.

The tax won't go toward relieving the infamous traffic jams at "Malfunction Junction," where Interstates 275 and 4 meet in Tampa, or for backups on the Veteran's Expressway — both the responsibility of state and regional agencies.

Still, those who back the plan say the county has to act. Some 700,000 people are expected to move to Hillsborough over the next 30 years.

"There is no question the downside to not doing it will mean 500,000 to 700,000 people will move into this region and we will have the exact same infrastructure we have today that has not been maintained adequately," said Tampa City Council member and mayoral candidate Harry Cohen. "To me, to not go forward with this is to court disaster for the entire region."

• • •

The city of Tampa has about 2,500 miles of roads.

Its current transportation budget is about $10 million per year.

Of that, about half is set aside for resurfacing, enough to fix 30 miles of roadway every year.

On that schedule, wear and tear on most roads will go unchecked for 75 years, Duncan said. By the time maintenance crews arrive, potholes are deeper and wider, repairs more expensive.

The city's share of proceeds from the transportation tax would be about $33.7 million per year. That infusion of money would boost the annual resurfacing budget to $12.1 million, enough to get the city's roads on a 25-year maintenance schedule.

It's a similar story with sidewalks and bike trails. The city's current annual spending of $900,000 is enough for just half a mile of new sidewalk.

The tax would boost that to about $5 million per year. It would also provide almost $10 million annually for safety measures like flashing crosswalks and sidewalks near schools, Duncan said.

"We would have a tenfold increase in dollars that we could use to build more sidewalks around our schools and in our neighborhoods," Duncan said.

Intersection improvements on Cross Creek Boulevard, resurfacing of Himes Avenue, the widening of New Tampa Boulevard and several other road projects could also be funded, Duncan said.

Most of the tax share that's earmarked for roads and trails would go to Hillsborough County — about $109 million per year.

That's on top of a 2016 commitment by commissioners to spend $600 million over the next 10 years to fix roads, bridges, sidewalks and intersections. It's unclear if the county would reallocate some or all of that money should voters approve the sales tax hike.

The 2016 plan falls well short of the amount needed to pay for the county's backlog of roadwork or to meet the demands of the fast-growing south county where new subdivisions are appearing.

If the tax passes, the county will look at bringing forward a number of projects from its 10-year work program that were never funded, said Public Works Director John Lyons.

That could include the completion of a South County trail that connects the Tampa Bypass Canal to Manatee County and the addition of intelligent traffic systems to Waters Avenue and Lumsden Road.

It could also pay for the widening of 19th Avenue in Ruskin to help address a deficit of east-west connector roads between U.S. 41 and U.S. 301 in south Hillsborough.

"We have a great backlog of work that is unfunded," Lyons said.

• • •

In past transportation referendums, rail has been a rallying point for opponents.

That was particularly true for the 2014 Greenlight Pinellas plan, whose $1.6 billion, 24-mile light rail service from St. Petersburg to Clearwater was derided by the group No Tax for Tracks as a train no one would ride.

The plan proposed by All for Transportation includes mass transit linking the university area, downtown Tampa and Westshore, but does not commit the county to rail. Instead, the plan promises only a transit system that has its own right of way, meaning it could not be held up by road traffic.

Whether that would be rail, light-rail, bus rapid transit or a combination has yet to be determined. Still, the long range blueprint from the Metropolitan Planning Organization offers a few clues.

It shows that the segment between the university area and downtown Tampa would use an existing CSX rail corridor. Cost estimates in the plan assume the corridor will remain as rail. Adding a passenger service to the existing line would cost $296 million and another $54 million to run for the first 10 years, the plan says. Some of the funding would come from federal and state grants.

The link between downtown and Westshore would use track now traveled by the TECO Line Streetcar System as well as state Department of Transportation right-of-way along Interstate 275. The plan is based on building a modern streetcar line at a cost of $456 million. It would cost $57 million to run in the first 10 years.

Officials stress that any transit system has yet to be designed so no choice has been made. Whichever alternative is chosen, HART would build and run it.

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HART's operating budget of about $70 million is the smallest of any bus agency in a community its size in the nation. In 2017, HART was forced to redraw bus routes to save money.

The new tax would swell the agency's funding to about $200 million in 2019.

HART board chairman Les Miller, also a county commissioner, said HART will begin planning for the tax only if it passes. But Miller expects the agency would return bus service to many communities where it was cut.

Barely served communities like Ruskin, Sun City Center and Wimauma could see new services added.

"We will meet the needs of what citizens want," Miller said.

Most residents agree that congestion has become one of the county's most pressing problems but that doesn't mean they think a sales tax is the answer.

Call center manager Lindsay Graden has to sit through four or five red lights to get onto Big Bend Road every morning. It takes her 55 minutes to drive her daughter to her private Christian school in Brandon.

Graden blames the congestion on the hundreds of new homes the county has approved without increasing road capacity.

"The county is reactive not pro-active," she said. "Why should we have to pay again?"

Apollo Beach information technology professional Cindy Hoos also plans to vote "no" on the ballot measure. But her husband, Terry Hoos, is a firm "yes."

"I'm willing to pay my fair share so the roads are the way I want them to be," Terry Hoos said. "It's a shame it has to be a sales tax."

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