DALLAS -- Gov. Rick Perry has proposed the Trans-Texas Corridor, and now his political opponents are making it a big issue in the race for governor.

It would cost billions of dollars to build a new highway running across Texas near Interstate 35.

I-35 is the only major north-south corridor in the state of Texas.

“It’s impossible to widen the highway in some areas,” Texas Department of Transportation spokesman Mark Ball said. “So the alternative is to build a separate corridor.”

But the Texas Transportation Corridor is much more than just a highway from Mexico to Oklahoma, blazing a trail three times wider than the average highway -- wide enough for more than just cars and trucks.

“The corridor is for rail, it's for commercial use for trucks, it's for private use, and it's also for utilities,” Ball said.

But opponents said the Trans-Texas Corridor is too big, even for Texas.

“Twelve hundred feet wide is far more than your average interstate. Your average interstate would be about 350 feet wide,” corridor opponent Linda Stall said.

“You're putting traffic lanes with high-speed rail and all the high fencing that goes with that, creating a barrier across Texas, dividing Texas everywhere it goes,” Stall said.

North Texas transportation leaders support the project.

"If we don't have this avenue that we're going to add to our infrastructure, then Texas is going to begin to go backwards as far as our economy, as far as jobs, because once we lose our infrastructure and our transportation, everything goes downhill from there,” Denton County Commissioner Sandy Jacobs said.

But leaders said they want the corridor to go around both sides of the Dallas/Fort Worth Metroplex.

“What that does for us is that it integrates a within-region route and an inner-city route into the same right of way,” North Texas Council of Governments Michael Morris

Because tolls would pay for the corridor, it guarantees transportation will remain a big campaign issue.