The construction of third lanes in the north and southbound lanes between exits 44 and 48 on the Maine Turnpike is nearly complete.

The $146 million project has been four years in the making.

Beginning Wednesday morning, a new third lane will open from Exit 47 south.  

On Thursday starting at 11 p.m. and ending Friday at 5 a.m., Exit 44 will be closed to restripe and open the new lane between exits 44 and 46.

The new lane will be open northbound from Exit 44 to Exit 46 Friday morning.

The remaining section is anticipated to open later this fall.

“This project will have a dramatic impact on reducing congestion through this busy corridor,” said Peter Mills, the Turnpike Authority’s executive director, in a news release.  

The $146 million project included rebuilding bridges and lengthening overpasses in four locations and improvements to five interchanges.

From Mile 43 to Mile 49, the median guardrail was replaced with 36-foot-high concrete barrier and a paved median to making it safer to work on disabled vehicles, according to the release.

“Another reason we widened this section is that we wanted to do an even better job of keeping traffic off of I-295 through Portland,” Mills said. “The Turnpike’s mainline, now wider and more efficient, is designed specifically to handle higher traffic volumes. It’s straighter, access is limited, and it’s the shortcut around downtown Portland,” Mills said.

“Since 1947 when the road first opened, Turnpike traffic through Portland has increased 25-fold. Demand surpassed the design of this section some time ago,” turnpike authority spokesperson Erin Courtney said.