Building a new I-5 bridge over the Columbia River is an idea you can now picture.

New computerized renderings show what the multi-billion dollar options look like.

"What we're trying to do is find that solution that works best for everybody," explained John Osborn, Co-Director of Oregon and Washington's joint Columbia River Crossing Project.

The states are studying a narrowed list of bridge options.

The total price tag: no more than $4.1 billion.

"Keeping the existing bridge is about 10-15 percent cheaper," he said.

A computerized rendering shows how that would look.

An additional transit-and-pedestrian bridge would be built next to the current I-5 auto-traffic bridge.

A second rendering created by the Columbia River Crossing Project depicts an entirely new replacement bridge over the Columbia with a smaller transit-and-pedestrian bridge built right alongside it.

A third rendering shows a replacement bridge with all rapid transit and bike traffic on the inside lanes of a new, larger bridge.

New data shows the replacement options would be safer; they would take up less space in the water thereby improving river traffic; and they would create smoother car traffic flow in downtown Vancouver.

Not only is there a choice of which type of bridge to build, there's also a choice of what kind of rapid transit to put on top of that bridge.

Option one: light rail MAX train.

Option two: something called "bus rapid transit."

"Light rail on wheels" is how Osborn explains it.

Putting buses on a dedicated express lane across a new bridge would be cheaper up front than light rail but it'd be less efficient and more costly to operate in the long run.

What are the chances of getting such an expensive project done?

Osborn says, "Very good. I hope."

The states' 39-member citizen advisory task force meets again Tuesday night with final recommendations coming in February.

Soon thereafter, the the federal government must decide how much money it wants to pitch in.

To help cover the cost, a replacement bridge over I-5 would likely be a toll bridge.

If the project is fully funded, construction would start in late 2010.

Planners hope to see a ribbon-cutting sometime in 2017.