A trio of Southwest Washington lawmakers are floating a new plan for an Interstate 5 span between Vancouver and Portland they say could alleviate congestion at a much lower cost than the failed Columbia River Crossing project.

State Rep. Liz Pike, R-Camas, detailed the proposal in a memorandum emailed to dozens of other lawmakers and local officials this week. She dubbed the idea the “I-5 Practical Design Fly-over” and said it could be built for $1 billion to $1.5 billion. In an interview, Pike cautioned that the idea is just that — an idea, not a concrete plan.

“This is one option,” she said. “I’m certainly open to listening to other ideas.”

The concept goes something like this: Build an extended “fly-over” bridge roughly from Mill Plain Boulevard to the vicinity of the Portland Meadows racetrack in North Portland, bypassing the most problematic interchanges near the Washington-Oregon state line. The existing Interstate 5 Bridge would be left in place for local traffic between downtown Vancouver and North Portland, including Hayden Island. The concept does not include light rail.

In her email, Pike said she, Sen. Ann Rivers, R-La Center, and Rep. Lynda Wilson, R-Vancouver, have worked to advance the idea. It was developed by Dave Nelson, a retired engineer in Vancouver who says he worked on his own time.