Maine is barreling down the road on a more than $200 million infrastructure investment that even its own backers agree is not enough to fix the current problem and could make things worse in the future.

It’s the proposed Gorham-Westbrook connector, a five-mile toll road being developed by the Maine Turnpike Authority, which could begin applying for permits later this year.

This is a long-desired project for people in the fast-growing towns west of Portland, who have seen traffic congestion clog their streets and slow rush-hour commutes. The Legislature assigned the Turnpike Authority to study the problem, and in 2012 it issued a report that proposed a new road that would take through traffic out of the villages.

But the report also makes clear that a new road won’t solve the problem on its own. The study found that developing a regional public transportation strategy as well as efficient land use-policies that direct growth away from single-family homes on large lots would be equally important if the project was going to succeed.

Ten years later, however, the new highway project is ready to go, while everything else is still on the drawing board.

Don’t blame the Turnpike Authority: It’s much easier to build new roads than it is to change old development patterns. But letting one part of the solution get so far out in front of the others could reinforce the conditions that are causing the traffic problems.

It’s a well-documented phenomenon that new roads lead to more driving. If you build them, they will come.

It’s called “induced demand.” History shows that it’s not just the people who currently use the old, congested thoroughfare who will use the new one. Drivers who used to plan their trips around high-traffic hours are less careful, and others take on longer-distance commutes thinking the new road will get them where they need to go on time.

From Boston to Los Angeles, road construction has proven to be a temporary relief at best.

The Turnpike Authority is a quasi-governmental agency that is fully funded by the tolls it collects, mostly from out-of-state visitors. Putting it in charge of this project was an attractive choice for the Legislature, which has a perennial problem paying to maintain the roads and bridges that exist already.

But traffic congestion in Westbrook, Scarborough, Standish and Gorham is not just a highway problem.

Its root cause is decades of economic pressure that make people look to once-rural areas for more-affordable housing. A lack of infrastructure, such as public water and sewer, demands that those homes be dispersed, making a car or multiple cars a necessity for every family and putting strain on roads that were built when traffic was much lighter.

Even though these towns are some of the fastest-growing in Maine, public transit is not viable because the population is so spread out. Without allowing for denser development and offering a real transit alternative, building a faster road from Gorham to Portland could simply drive the development further west.

In a recent forum hosted by GrowSmart Maine, a group that advocates for sustainable economic development, planning officials from Gorham, Standish and Scarborough spoke about the policies they are developing that would focus growth and increase density in village centers if they had a solution to their traffic problems.

The Greater Portland Council of Governments, a regional planning agency, recently received $800,000 in federal funding to study a rail or bus rapid-transit link on the 12-mile corridor between Gorham and Portland.

The results of that study could provide a clearer picture of whether a new stretch of highway would improve regional traffic or create new problems.

These efforts deserve the time needed to catch up with the Turnpike Authority. This is not just a question of how to move existing traffic, but deciding how the region will accommodate growth over the next decades.

Until we know where we’re going, this project should slow down.