Transportation planners may think of six-year capital programs and 20-year vision statements, but commuters tend to live for today. In online discussions, they often ask about the timing on a traffic light or the closing of a lane. So a comment titled “Dream project” got my attention during Monday’s chat.

Dr. Gridlock,” the commenter wrote, “if money were no object, in your opinion what one transportation-related project — new or improved road, bridge, Metro line, high speed train line, etc. — in the greater D.C. area would have the greatest positive impact on transportation?”

Of course, money — or the lack of it — is a very big object in the path of a better transportation network. But travelers are so ground down by their commuting experiences that it’s sometimes a pleasure to see what grand possibilities they imagine.

So I started: “I would create that regional network of rapid buses that we’re always talking about. What I want is something that has the potential for a high impact on living commuters, not people who will be commuting 40 years from now.

“The thing on your list that I’d be least likely to pick is high-speed rail. Huge investment. Unrealistically high ticket prices.

“Very curious what one project others would pick.”

“That’s easy,” one commenter replied, “another Potomac River crossing between the American Legion Bridge and Point of Rocks. It’s pathetic that there’s only one bridge connecting two of the richest counties in the United States (Fairfax and Montgomery). The AL Bridge is already past its design capacity, and traffic isn’t getting any lighter.”

Others were similarly inclined toward new highways: “I would have to say an eastern bypass. Trucks account for such a large percentage of the vehicular traffic on I-95, even during rush hour, and most of those trucks are just passing through the region. I-81 represents a significant detour for most truckers traveling the Northeast Corridor. A bypass of the region to the east (perhaps including parts of I-97 and U.S. 301 with an improved Harry Nice Bridge) would represent a viable alternative for interstate commerce through the area.”

Overall, travelers split about evenly between ideas for highways and ideas for transit. Sometimes, they combined modes: “Add a new bridge into Virginia, and underneath it, another tunnel for the Orange/Blue lines.”

One commenter pointed out the downside of my idea and offered a very good alternative, given that our premise was unlimited resources:

“Unless BRT [bus rapid transit] is done right (i.e. separated rights-of-way, really, really frequent headways, etc.), it is doomed to failure as an effective and fast means of transit. It will also do little to alleviate overcrowding in the core of the Metrorail system.’

“What would make far and away the greatest impact on regional commutes is the oft-dreamed-of separated Blue Line, which would expand access to Metro in the downtown core including areas like Georgetown, Logan Circle, and H Street, help streamline existing service along the downtown Orange/Blue track (which would become just Silver/Orange), create an additional Potomac crossing which is long overdue, and allow for more and better connections from Union Station, which deserves to be a true transit hub for the city.

“It’ll be a billion-dollar project, but worth every penny. Additional Metro lines that open up new neighborhoods of D.C. to more density and development — particularly northern areas like 16th Street Heights — would also make a huge difference. And in what is a fast-growing city, there’s no substitute for the speed of underground heavy rail.”

The idea of adding another tunnel — or at least another track — through downtown D.C. drew many supporters.

Here’s another very good choice, and probably the cheapest, easiest and highest-impact of the bunch:

“If I had the money and human resources, I’d work on something that obviated the need for so many of us to commute in the first place. Better virtual work environments ... holograms of my colleagues shooting out of my iPhone while I work from home.”

I realized that our discussion accounted for unlimited funds, but not for unlimited political power. Proposals like the extra bridge or the bypass or the new rail tunnel would need a great deal of political support as well as a huge amount of money. Both are in short supply.

What’s your big idea?