Lawmakers looking to relieve traffic congestion in Nashville have hit upon an improbable solution: a monorail.

The stretch of I-24 between Nashville and Murfreesboro is one of the most congested in the state, and it's projected to get even worse as the population grows.

So State Senator Bill Ketron, a Murfreesboro Republican, proposed building a monorail along the highway median. While it may sound ridiculous at first, the idea is getting some traction.

In fact, the Tennessee Senate voted 31-0 to conduct a monorail feasibility study. If it passes the state House of Representatives, the Tennessee Department of Transportation will have to determine whether it makes economic sense to build a 30-mile elevated monorail for suburban commuters.

Yes, we saw two monorails torn down this year, and the concept hasn't caught on in the U.S. outside of Seattle and Disney World. But hold the Lyle Lanley jokes, because the Nashville monorail might just make sense.

See, there are two major costs when it comes to building a brand new public transit system from scratch. First, there's the cost of construction. Building a monorail can be extremely pricey–it's a lot harder to put up an elevated track than to lay one on the ground.

But monorails can come out ahead when it comes to the second major cost, and that's land acquisition. You can't just put a train through a built-up area without buying up land first, and that can get extremely expensive.

The Nashville monorail would be built on the median of I-24, so the state wouldn't have to acquire land from private owners.

That was one of the main reasons why São Paulo decided on monorails for its latest public transit service: Putting trains underground would be too expensive, and the city was too congested for more surface-level transit.

We'll have to wait and see. Ketron's plan could cost as much as $1 billion, and calls for public and private funding sources include a potential 90 percent contribution from the federal government.

If the feasibility study is approved, the Department of Transportation will have to report its findings by Feb. 1, 2015. And after that, the U.S. could get its first monorail in decades.