At a news conference Wednesday, members of the Sierra Club and Utahns for Better Transportation presented an alternative plan to the 14-mile Legacy Parkway, including commuter rail, light rail and extensions of Redwood Road to Centerville.

Only 12 acres of wetlands would be affected with the plan, instead of the nearly 100 acres affected by Legacy. The entire project would cost about $200 million, according to the groups' estimates.

"Our idea is vastly better in terms of meeting the need to protect the wetlands," said Lawson LeGate, Sierra Club regional representative.

But officials with the Utah Department of Transportation -- while saying they are encouraged by the proposal -- were skeptical it would pass muster without Legacy.

"Legacy is absolutely a critical piece of the puzzle when it comes to solving transportation in Davis County," said UDOT spokesman Tom Hudachko.

That's something that was reaffirmed by the 10th Circuit Court in Denver, he added.

In 2001, the court put a stop to construction of the road in a ruling on a lawsuit by the Sierra Club, Salt Lake City Mayor Rocky Anderson and Utahns for Better Transportation.

The court said UDOT needed to be more thorough in studying the roadway's location and width, impact on wildlife, transit integration and sequencing of projects -- a decision about when Legacy, commuter rail or an expanded Interstate 15 should be built.

And there's no question about whether Legacy should be built, said UDOT Executive Director John Njord.

"The growth is happening whether the road is built or not," he said.

During a meeting with The Salt Lake Tribune editorial board, Njord presented a draft copy of the supplemental environmental impact statement UDOT has been working on since the 2001 lawsuit.

The study concludes that alternatives to the highway, including Redwood Road and an alignment farther east in the Denver and Rio Grande railroad corridor, are not feasible in terms of cost and impact.

Shifting the road farther east, would affect from 149 to 279 homes and cost hundreds of millions of dollars more. The Legacy Parkway, in its preferred alignment, will cost approximately $468 million.

"The impacts would be significant," said Njord.

But Marc Heileson with the Sierra Club disagrees. Transit would work -- and work well -- if given a chance.

"We consistently have underestimated transit," he said, pointing to the growth in TRAX ridership in Salt Lake County. UDOT's projections "don't even pass the laugh test when you see what is on the ground and running."

Under law, UDOT is required to look at the proposal by the Sierra Club and Utahns for Better Transportation and address any concerns about the Legacy Parkway project.

If not addressed, Heileson says the Sierra Club and others will fight back and that may mean another lawsuit.

"We're prepared to," he said.