How many roads across South Mississippi are getting wider? Here’s the list

South Mississippi’s roads are getting busy.

The region’s growing population is forcing state leaders to expand highways and add more lanes across the three coastal counties.

The work includes Interstate 10. The Mississippi Department of Transportation is in the middle of a $155 million project that will widen several miles in Harrison County from four to six lanes to fit more cars. The interstate is the Coast’s main thoroughfare, but it varies in width across the region.

Billy Owen, an MDOT district engineer who oversees South Mississippi, said state transportation leaders hope to change that.

“Eventually,” he said, “it’ll be widened from state line to state line.”

Here’s more about each road widening project currently planned or underway on the Mississippi Coast.

Interstate 10

Construction crews are widening Interstate 10 from four to six lanes between Diamondhead and County Farm Road. The $155 million project began in spring 2024 and will be finished in 2027.

MDOT has also already started studying how to widen I-10 in Jackson County, Owen said. The next project would likely run from Highway 57 to the Pascagoula River Bridge. There is no set timeline yet for the project, but Owen said MDOT is hopeful it can secure funding for construction.

Highway 49

MDOT is widening Highway 49 in Harrison County from four to six lanes between O’Neal and School roads.

The $44.9 million project began in summer 2024 and is scheduled to finish in 2026.

Highway 57

MDOT is also working on a project to widen nine miles of Highway 57 to four lanes. The work is happening between I-10 and Vancleave.

The $212.6 million project began in spring 2023 and is expected to end in 2027.

Highway 90

MDOT is planning to widen Highway 90 from four to six lanes between Highway 609 in Ocean Springs and Dolphin Drive in Gautier.

Owen said MDOT hopes to start construction in 2027.

This story was originally published November 18, 2025 at 9:10 AM.