The new signs show I-74 and U.S. 311 peeling off from Interstate 40 on the southeast side of Winston-Salem. The new section of I-74 doesn’t meet interstate standards until it gets to Guilford County, in part because it lacks the wide shoulders that interstate highways have for emergency stopping.

A letter in the online files of the N.C. Department of Transportation shows that federal highway officials believed the Forsyth County portion of the highway did meet interstate standards when they granting the road’s addition to the interstate system:

“Our North Carolina Division Office confirms U.S. 311 from I-40 to S.R. 1993 [Main Street in High Point] … has been completed to Interstate standards and meets a statutory requirement by connecting to existing I-40,” wrote Victor Mendez, the U.S. deputy secretary of transportation and administrator of the Federal Highway Administration in a letter to the N.C. Department of Transportation dated Oct. 4, 2012.

Mendez was referring to the N.C. Division Office of the Federal Highway Administration in North Carolina, not any of the N.C. Department of Transportation offices.

State officials said the designation has been allowed to stand even though the road lacks shoulders of the proper width.

A spokesman for the Federal Highway Administration had no specifics on how the mix-up occurred, but confirmed what state officials are saying: North Carolina will eventually bring the section of roadway up to interstate standards. The I-74 designation will remain.

“It is clearly an oversight and the state is committed to making things right, and that’s as far as it goes,” said Doug Hecox, a spokesman for the Federal Highway Administration.

No timetable has been set for adding the shoulders that section of I-74 needs, said Kevin Lacy, the state’s traffic engineer.

“We have agreed to bring those shoulders up to standards when we rebuild the roadway,” Lacy said. “You have to have a minimum of 10 feet on the right and four feet on the left shoulder. We do not have a project identified to put shoulders on that road. Whenever we rebuild that road we will have to add shoulders.”

The designation is significant because it makes the road eligible for federal maintenance money, and increases the state’s interstate mileage by about 10 more miles than it would otherwise have been. That mileage in turn increases the money the state receives for interstate maintenance under the fund-apportionment formula.

The state had intended all along to eventually make U.S. 311 part of I-74.

The designation came after an exchange of letters between state and federal highway officials that started in 2011. On Jan. 6, 2011, State Highway Administrator Terry Gibson wrote to John Sullivan III, the division administrator for the Federal Highway Administration in North Carolina, requesting interstate designation for a different segment of highway.

That letter requested that the new High Point East Belt — U.S. 311 east of the Main Street exit in High Point — become part of I-74, and that the segment of U.S. 311 from Main Street to I-40 “be added to the Interstate system as a Future Interstate, a distance of 10.17 miles.”

The letter noted that the new beltway around High Point and to points east “was recently completed to Interstate standards and open to traffic. The proposed I-74 route is a controlled access, divided, multi-lane freeway on a new location.”

Lacy sent a follow-up letter on March 15, 2012, in which he repeated the request for adding road segments to “I-74 and future I-74.”

Lacy goes on to mention that the “requested sections of I-74 were built to Interstate Standards at the time of construction.”

When asked if the references to “sections” — in the plural — may have led to some of the confusion, Lacy said that’s possible. A little later in the letter Lacy does refer to “the above referenced section” — in the singular — to refer the part of the road east of the Forsyth County segment that meets most interstate standards.

“I can’t tell you the source of the confusion other than to speculate,” Lacy said, commenting on his letter. “If that was part of it, it was by no means intentional.”

I-74 in North Carolina currently exists in a number of segments that are connected by noninterstate roadways. In the north, I-74 peels off from I-77 south of the Virginia line and carries traffic to U.S. 52 near Mount Airy. When the Northern Beltway is build around the east side of Winston-Salem it will be part of I-74 linking to the newly designated portion that runs along with U.S. 311 to High Point.

Past High Point, newer sections of I-74 connect to Asheboro, where I-74 joins I-73 heading south toward Rockingham. From there to its eventual ending point near Myrtle Beach, S.C., I-74 exists only as a stretch of freeway from Rockingham to Lumberton.

Lacy said Monday that it is “extremely rare” for the Federal Highway Administration to admit a section of highway into the interstate system without adequate shoulders.

“We did not ask for it at that time, but we were extremely appreciative,” Lacy said. “Prior to us doing anything and announcing it, we followed up with the Federal Highway Administration and said we wanted to be clear. We verified that … yes, there was a mixup somewhere. They asked us to send a letter saying that we would bring the shoulders up to standard.”

Lacy said that if there was an error, “it was in citizens of North Carolina’s favor” because of the benefits flowing from the designation. He said that it is possible the federal authorities could have rescinded the designation.

“Some people may classify this as a mistake,” Lacy said. “They gave us a rare exception, and it is a gift.”