AUGUSTA — Starting Monday morning, part of Mount Vernon Avenue becomes a one-way street headed north, leaving drivers looking to go south into the city from the Civic Center Drive area to find other ways to get there.

The decision to keep the road open to one-way traffic headed north, not south, was made in large part because the biggest priority was to not impede ambulances and other public safety vehicles rushing to MaineGeneral Medical Center’s hospital in north Augusta.

While those ambulances, police cars and fire trucks will still need to return south to Hartford Station on Water Street, other fire stations or the police department on Union Street, they’re much less likely to be in a rush coming from the hospital than going to it.

“We asked for it to be northbound, headed out of town, so anybody who is going to the hospital is not delayed,” said David Groder, deputy fire chief. “We generally haven’t been taking (Mount Vernon Avenue) anyway, because the road was so rough for patient care.”

The roughness of the road is what’s behind the major, $4.3 million reconstruction project that is expected to continue through June of next year.

The one-way restriction won’t be nearly that long, and, as specified in the contract for the work, the road is expected to return to two-way traffic within three months, according to the state Department of Transportation.

The section of the major thoroughfare through the city to be restricted to one-way is only about a half-mile long, from Mill Street near the Bond Brook Bridge just north of the Bond and Boothby street intersection to a fuel depot just south of Augusta Florist. The rest of Mount Vernon Avenue will remain open to traffic in both directions.

Ernie Martin, project manager for the state transportation department, said that section will be one way for up to 90 days because it is too narrow to allow two-way traffic as contractors rip up and reconstruct the road and work on drainage and other infrastructure there.

He, too, said the northbound direction was chosen out of public safety concerns and the location of the hospital.

“There has been a lot of early dialogue and planning with the city of Augusta, fire and police. That’s why we’re headed northbound,” Martin said Friday. “You want ambulances and others to be able to go north as quickly as they can, and on the way back they can take an alternate route. The northbound decision was purely one of safety. If the hospital was on the other side of the river, (the one-way direction of travel) would probably be the other way.”

Groder said the only potential delay related to the one-way for firefighters could be if there were a fire in a building on that one-way section. Even then, he said, the response isn’t likely to be delayed. He said firefighters at Hartford would still be able to get to a fire there directly, coming north, and firefighters from the fire station on Bangor Street would take an alternate route and approach from the north instead of coming south on Mount Vernon Avenue. He said they’ve done time trials on the alternate routes, and the response time was about the same as it would be before the change.

Martin said the state will monitor traffic flow and could make tweaks if needed.