CHAPEL HILL - A road project expected to cause major delays around UNC-Chapel Hill this spring could also cost nearly $2 million more to maintain existing bus service.

Triangle Grading & Paving Inc. of Burlington started installing signs and removing trees Tuesday from South Columbia Street. The $4.6 million project will add bike lanes, sidewalks, a center-turn lane and bus pull-offs to a busy 0.8-mile stretch between Purefoy Road and Manning Drive.

The two-lane corridor, located just south of the UNC-CH campus, is one of the busiest transit routes in the region, if not the state, Chapel Hill Transit Interim Director Brian Litchfield said.

While the contractor will limit lane closings initially, the southbound lane will close at Mason Farm Road, and all southbound traffic be routed to Manning Drive in April. That’s when the work could happen around the clock, N.C. Department of Transportation engineer Chris Kirkman said.

During the closure, Chapel Hill Transit will have to detour roughly 600 daily trips – about one bus every 90 seconds during the day and half its daily trips. The detour also will affect weekday bus routes that use Manning Drive and Mason Farm Road.

Chapel Hill, UNC-CH and Chapel Hill Transit officials met with DOT officials Thursday to talk about how to keep the public updated. They’ve got a lot of work to do before April, Litchfield said.

“It’s going to be (like having) a ‘special event’ every day on the UNC campus and around the hospital,” he said.

The cost of rerouting and adjusting bus schedules after April 1 could be $850,000 to $1.5 million, he said. If Chapel Hill Transit adds more buses and drivers to maintain the existing frequency of bus routes, the cost could rise to $1.25 million to nearly $1.93 million, Litchfield said.

The bus system’s three partners – Carrboro, Chapel Hill and UNC-CH – share responsibility for operations and costs. UNC-CH picks up 60 percent of the local tab.

While they expected the project to cost them money, Litchfield said they didn’t know when it would start because of years of delays. They will have to find $350,000 to $500,000 of the additional cost this fiscal year, he said.

The remaining money can be built into the 2013-14 budget. That, too, will be a challenge, given tight budgets and cost increases of 6 percent to 8 percent annually, he said.

Detouring traffic onto Manning Drive also will slow access to UNC Hospitals.

Mary Beck, senior vice president for System Affiliations at UNC Health Care, said they have not taken any specific steps to mitigate the effects. They are aware the work will create difficulties for emergency vehicles, patients and staff, and have told DOT that hospital access is important, she said. They want the project finished as quickly as possible, she said.

Officials have known about the possible effects for some time. DOT Division 7 Engineer Mike Mills said the parties met over a year ago to discuss potential problems. They also met for a pre-construction meeting Nov. 19.

While most urban road projects tie up traffic, this is unique because of how close it is to campus, Mills said. They tried to head off some problems by delaying the project until traffic signals were better coordinated, he said. That work was completed this fall. They also looked at routing traffic on Mason Farm Road but couldn’t make it work, he said.

“It’s going to be tricky to keep everything going,” he said.

Town and UNC officials have talked with DOT since 1997 about improving the narrow, winding road. Pedestrians and bicyclists are forced to share the road with often-congested traffic going into and out of downtown, the UNC-CH campus and UNC Hospitals.