A fog of uncertainty has been so thick for so long around the prospect of more rapid transit lines — bus or rail — in these Twin Cities that I didn't expect much excitement at last Monday's public meeting on the proposed Riverview Corridor line.

Why get hot under the collar on a beautiful summer's evening about a transit project that's in about fifth place in Metro Transit's build-out queue, when question marks still hang over the two light-rail extensions that are slated for the start of construction next year, Southwest and Bottineau?

My expectations were upended as I walked into Dowling Elementary School in Minneapolis and spotted the printed red-and-white signs that some attendees were toting. "No tracks on 46th Street!" they read.

Inside, angry voices were easy to overhear around the large posters describing six options for an improved transit connection between downtown St. Paul and Minneapolis-St. Paul International Airport.

"It's a joke!" I heard at the poster that detailed cost projections for some of the six mode-and-route options under consideration: $1.2 billion for a streetcar line through the former Ford factory site that crosses the Mississippi River at Ford Parkway; $1 billion to $1.1 billion for a streetcar on W. 7th Street that crosses the river at — and could tunnel near — Fort Snelling. Lower-cost regular bus service and bus rapid transit on existing streets via the W. 7th Street route round out the options.

If streetcars through the Ford site are chosen, "they're going to kill off the existing neighborhood!" said an agitated John Hackett. He's lived for 30 years near the 46th Street Station in Minneapolis, where a Riverview streetcar line might connect with the existing Blue Line.

I stifled a retort that change is coming to some existing Minneapolis and St. Paul neighborhoods whether residents like it or not — and whether Riverview and the other transit lines on planners' drawing boards are built or not.

An estimated 824,000 more people will be living in this region by 2040, population experts say. Many of those additional residents will need and/or want to live in densely developed urban settings as the cost of sprawl climbs. Some of that development is bound to come to neighborhoods now dominated by single-family homes — or near to them, as will be the case in St. Paul's Highland Park with the planned redevelopment of the Ford plant site.

The transportation issue for the neighborhoods near the Ford site isn't streetcars vs. the status quo. It's streetcars vs. a lot more cars and buses crossing the Ford Parkway bridge and clogging their streets.

Through that lens, modern streetcars — which run on tracks embedded in roadways that cars use, too — ought to have some appeal. But that wasn't the view of the locals at Monday's public meeting. They registered concern about streetcar noise, risk to pedestrians, loss of houses, and cost and congestion on 46th Street and the bridge.

Streetcars are included in four of the six options still in the running for the Riverview line's "draft locally preferred alternative," a designation that's due to be bestowed in October. Then come a few more months of deliberation before a "locally preferred alternative" is named. Then come another round of meetings on design, environmental impact, community impact and who-knows-what. The timeline distributed at Dowling listing the project's remaining hurdles simply says "stay involved" after 2018.

It's a gantlet with plenty of opportunity for detours and derailments — but it's a surer path than existed a few months ago. The 2017 Legislature reached a truce in its long-running light-rail war. It allowed Hennepin and Ramsey counties the freedom to take charge of new rail projects. Those counties' boards are raising the sales tax rate 0.25 percentage points to provide a dedicated funding stream to pay for Southwest, Bottineau and the other projects on their wish lists.

But the federal funding on which such projects are highly dependent has been proposed for elimination by President Donald Trump — and while Congress so far appears to be ignoring his suggestion, presidential hostility is never a small matter. Designing a project that meets federal requirements for cost and ridership is never easy. Designing one that avoids lawsuits could be impossible.

To all of that potential uncertainty, add the arrival of self-driving cars. Minneapolis City Council Member Andrew Johnson, whose ward includes the "no tracks" sign-toters, thinks they could change a lot of transit plans.

"Self-driving vehicles could be 'last-mile' vehicles, taking people to transit lines. Or they could allow us to increase the carrying capacity of the existing infrastructure to such an extent that they negate the need for more transit options," Johnson said, noting that self-driving cars can operate safely at closer proximity to one another than cars with human drivers.

"We're far enough along with self-driving cars to know they'll be here soon, yet not far enough to fully understand how this will change our plans," he said. "It may change the whole equation."

Johnson was speaking to me, but his words seemed intended to soothe his streetcar-averse constituents. More reason for indecision and delay probably sounds good to them.

But delay shouldn't sound good to the rest of this region. Inadequate transit is already putting the Twin Cities at a disadvantage in the competition for the vital economic input that's forecast to be in short supply in the next two decades — young talent. Modern bus and rail rapid transit is a talent magnet, as cities like Seattle, Denver, Portland and Dallas are proving. Wooing more millennial-generation workers to Minneapolis and St. Paul in the next few years while they are still in their footloose 20s and early 30s will pay this region dividends for decades to come.

The fog of uncertainty around proposed rapid transit lines may be a comfort to those who live near them. But the rest of us have reason to root for that fog to lift as quickly as possible.

Lori Sturdevant is a Star Tribune editorial writer and columnist. She is at lsturdevant@startribune.com.