LOS ANGELES, Calif.–Voters will decide today whether to extend a half-cent sales tax for an additional 30 years to accelerate public transit and highway projects, including the Westside Subway Extension and transit to Los Angeles International Airport.

In 2008, Los Angeles County voters approved Measure R, a 30-year half-cent sales tax increase to fund major transportation projects and bus and rail operations. The tax is set to expire in 2039. Voting for Measure J would extend the sales tax to 2069, raising an estimated $90 billion. The extension would allow the Los Angeles County Metropolitan Transportation Authority to raise bonds against the future revenue to pay for transit projects sooner.

The tax extension requires support from more than two-thirds of voters.

Measure R passed narrowly with 67.9 percent of voters in favor.

According to Metro, Measure J would allow completion of the Purple Line subway to Westwood 14 years early in 2022. Connecting the Green Line to LAX could happen by 2023 instead of five years later.

Other transit projects that would be accelerated include a transit option along the San Diego (405) Freeway through the Sepulveda Pass, an extension of the Gold Line to either South El Monte or Whittier, and an extension of the Green Line into the South Bay.

Proponents of the measure include Los Angeles Mayor Antonio Villaraigosa and the region’s labor unions, who say extending the tax will allow Metro to accelerate big transit projects, creating jobs and building out the region’s public transit network to relieve traffic. Building the projects now is a good idea, supporters say, because building and borrowing costs are low. Metro predicts the agency would pay about a 2.7 percent interest rate on the bonds.

“There is quite literally nothing on the ballot that will improve Los Angeles more dramatically and faster than voting for Measure J,” said Measure J Campaign Director Matt Szabo, who is also running for Los Angeles City Council in the 13th District. “At a time when unemployment in the county is up above 10 percent, this measure will create 250,000 jobs in next decade.”

Opponents of the measure include the chairman of Metro’s own Board of Directors, Los Angeles County Supervisor Mike Antonovich.

“Overall, Measure J completely over-promises what it can deliver and doesn’t bring to light the impact it’s going to have on fares,” said Michael Cano, Antonovich’s senior adviser on transportation. “Measure J will ensure that fares will increase at a faster rate in the upcoming years to handle any new operations associated with future projects.”

A Metro report from earlier this year suggested service costs could outpace the agency’s revenue by 2017, possibly leading to fare hikes for buses and trains.

Cano also called the tax extension “an attempt to burden decades of future generations of L.A. business owners and people with debt to try to accelerate projects now that would otherwise be built in segments.”

Szabo countered that the measure is about building the region’s transit system for the long-term, “something this county has failed to do.”

“If we pass Measure J and accelerate these projects, we will be paying for services we will actually have the chance to receive in our lifetime,” Szabo said. “Our grandchildren will be benefiting from everything that we’re building. The notion that we’re putting the cost of this off to our grandchildren is absurd.”

Damien Goodmon of the Crenshaw Subway Coalition said Metro cannot be trusted to spend the bond money fairly. Goodmon is an outspoken critic of Metro for not including any money for a light rail station along the planned Crenshaw Line in Leimert Park Village, which many consider to be an economic center of L.A.’s Black community.

“This agency is not responsive to community concerns or bus riders when it makes decisions,” said Goodmon, who also criticized Metro for building more transit projects than it has money to operate.

“Before you engage in a $90 billion process like this, you should prove you can run it,” Goodmon said.

“Would you buy a car if you didn’t have the money to pay for gas or insurance? No.”

Organizers with the Bus Riders Union said new rail projects will mean cuts to bus service, which will hurt the city’s working class residents who use the system.

Szabo disputed the claim, saying 20 percent of Measure J revenue–or about $18 billion–will be dedicated to operating buses.

“This will be the biggest shot in the arm for a first-class bus system we could possible provide,” Szabo said.

Rounding out the No on J coalition is the Beverly Hills Unified School District, whose board voted last month to oppose the measure as long as the Westside Subway Extension involves tunneling under Beverly Hills High School.

District board members say tunneling will interfere with the district’s plans for a renovation at the school and any other future building plans.

School Board President Brian Goldberg said last month that Metro has “has repeatedly refused to hear our valid concerns about locating the subway under instructional buildings at Beverly Hills High School, and have shown a complete disregard for the will of the people of Beverly Hills on this matter.”

The school district has sued to block the subway extension.