Since 2013, road construction companies working for the Michigan Department of Transportation have been slowly replacing a couple of I-94's crumbling overpasses in Detroit each year.

By 2039, they should be all done.

You read that right.

In nearly 20 years, Michigan may finally complete rebuilding one of the nation's first interstate highways this state helped invent in the 1940s and 1950s.

The $2.9 billion remaining price tag for a project would effectively eat up the Michigan Department of Transportation's capital budget for nearly three years if it were to focus only on replacing I-94 in Detroit.

But there is a potential solution to waiting two decades to fix this economically vital thoroughfare: Charge tolls.

Converting I-94 in Wayne County to a toll road would create a future revenue source that could be bonded against to generate the money needed to speed up this reconstruction project. The bonds could be repaid through future toll revenue.

As Lansing enters the 10th consecutive year of a debate over long-term road funding that almost always revolves around fuel taxes, it may be time to explore different approaches to financing transportation infrastructure for specific projects of utmost importance to the state's future.

While taxing gasoline and diesel remains the fastest way to generate more revenue for roads, motor fuel taxes also are a dying form of taxation likely to shrink over time as automakers move to increase fuel efficiency and electrify their fleets.

"If you only do a gas tax, mark my words, in 10 years we'll be having the same conversation," said Eric Morris, a vice president at HNTB who leads the transportation engineering and planning firm's Michigan offices. "We have to find a new revenue stream."

HNTB is MDOT's program manager for the I-94 reconstruction project.

"The biggest constraint we have on the program right now is not knowing what to do. It's funding," Morris said.

In recent months, Morris has been advising Gov. Gretchen Whitmer's office and lawmakers on how toll roads paired with bonding could be a viable means for financing highway reconstruction and maintenance, freeing up existing funding for other trunkline roads.

Whitmer's office is listening and studying tolling as one of several alternatives to road funding after her 45-cent-per-gallon fuel tax hike sputtered out in 2019.

"Given the Legislature is not serious about fixing unsafe roads and bridges, the responsible thing to do is examine other options to protect Michiganders," Whitmer spokeswoman Tiffany Brown said in a statement.

A myth that's been spread in the Capitol for years is that the federal government won't let Michigan create toll roads on existing roads.

It's complicated, but it can be done.

Congress and the U.S. Department of Transportation have created options for states that could allow for tolling on metro Detroit's freeways.

With approval from the federal government, Michigan could potentially:

Toll "federal aid" roads where bridges need to be replaced. This could be the pathway to tolling I-94 from Michigan Avenue on the Detroit-Dearborn border to as far east as the Roseville exits in Macomb County. It also could be deployed elsewhere in the state, assessing a toll for every bridge crossing over another road or a body of water.

Convert High Occupancy Vehicle (HOV) lanes to a toll lane. Michigan doesn't currently have any HOV lanes, but the fourth lanes being added to north and southbound I-75 in southern Oakland County are intended to be HOV lanes that could be used for variable-rate toll lanes.

In other words, motorists in the HOV lane could be charged a lesser toll than single-occupant commercial trucks and passenger vehicles in the other lanes. HOV lanes could, in theory, be added to other metro Detroit freeways, such as I-696, I-275 and I-75 in Wayne County, and then converted in the future to toll lanes

The express lanes on I-96 on Detroit's west side could be tolled at a different rate than the local lanes, which are already physically separated. The local lanes also could be free for residents traveling from between exits, while a commuter from Northville could be charged a toll to drive in the express lanes. California, Florida and Virginia have created these so-called "Lexus lanes."

The other myth is that it would require a massive upfront infrastructure bill to add toll booths and build new interchanges to create a Chicago-style toll road.

That's a 20th century way of thinking about tollways.