CHARLOTTE, N.C. -- Transit leaders say the sound of the light rail whistle is the beginning of a fulfilled promise, a promise made to voters in 1998 when they approved a half-cent sales tax to begin building and expanding mass transit.

Rachel Bennett used to live in a city with trains and is excited to have them here.

“I think its a lot better for the environment. Hopefully people will use it to as a way of getting around besides using their cars, Hopefully a lot of professionals will use it to commute,” she said.

But has Mecklenburg County gotten what voters approved nine years ago?

“In my estimation, we have,” said Ron Tober, CEO of the Charlotte Area Transportation System.

Tober said CATS has delivered the expanded bus system and the new light rail promised in advance of the 1998 referendum.

“I think we've done it even a lot faster than most people expected us to do, with the first part coming on this year,” he said.

The transit tax was sold in 1998 as part of a 2025 transit and land use plan for Mecklenburg County. The goal: to relieve traffic congestion and pollution.

The south corridor's light rail line was supposed to cost $227 million. Now it looks like the full tab will be twice that -- $462 million. Construction costs have soared, so with limited funds the timeline for all the county's corridors was pushed out five years.

“The 2030 plan as it stands now, I believe a significant number of our citizens don't believe that that’s the best way to utilize that half-cent sales tax,” said Karen Bentley, Mecklenburg County commissioner for District 1.

Bentley said as voters decide whether to keep the current half-cent tax, they're asking critical questions.

“Is it reducing congestion to the degree we hoped for in 1998 when we voted for it? Is it addressing air quality like we were told in 1998?” she said.

Bentley believes the answer is no on both counts. She said voters tell her some of the transit tax money should go to widen congested roads, and killing that tax may be the only way to stop the current plan in its tracks.

“I think if the tax goes away, they're going to have to have a discussion about it. If the tax stays. it’s status quo with the plan as it stands,” she said, adding that the status quo is unaffordable.

Tober said the issue may not be affordability but patience.

“The plan is affordable solely with the half-cent tax. The trade off is it will take longer than what we told them in 1998,” he said. “The plan was a 2025 plan. Now it’s 2030 or beyond to put all the improvements in place.”

Critics of the transit plan say neither increased bus use nor the new light rail will be enough to make a dent in congestion or pollution, and Tober admits one failure of CATS is selling its vision of mass transit to the public. Now the question is whether voters will continue to buy with their tax dollars.

It’s important to note, Bentley mentioned the idea of using the half-cent sales tax on roads. That cannot be done now because the 1998 referendum called for using those funds for mass transit.

If the tax dies, that would send transportation leaders back to the drawing board to figure out where to get money and how to spend it.