COLUMBIA — Plans for a $534 million upgrade of Interstate 526 came into sharper focus on Wednesday as a top state engineer explained the project to the people who must approve it.

The I-526 work includes six-laning the 19-mile length of the four-lane highway, improving traffic flow at its congested intersection with Interstate 26 and bridge rehabilitation work, said Ron Patton, state Department of Transportation chief engineer for location and design.

I-526 is among seven interstate projects totaling $1.7 billion that Patton presented to a joint meeting of the state DOT Commission and the state Transportation Infrastructure Bank Board.

Design work for I-526 is slated to begin next year, he said, and the first phase of construction will start in 2019.

The players who are key to the interstate project's moving forward seemed to be on the same page. Infrastructure Bank Board Chairman Don Leonard and DOT Commission Chairman John Edwards said it was time to get going on the effort.

“Just as soon as possible, start paving roads,” Leonard said.

The only note of concern sounded during the hour-long meeting was when state Sen. Hugh Leatherman, a member of the bank board, raised the issue of assurance that legislative funds approved for the work are properly allocated by the DOT.

“I don't want that $50 million to get over to DOT and wind up somewhere other than the General Assembly intended,” Leatherman said.

Legislators this year approved a $50 million annual allocation to the DOT that it will send to the bank board to help finance its prioritized list of highway upgrades.

Leatherman also advocated that interstates be widened into the median because the ground there has already been stabilized. That is the plan for I-526 widening, Patton said.

Leonard sought to address concerns that the bank board would not see eye-to-eye with the DOT on its ranking of interstate rehab projects.

“We are exactly in line,” he said.

He said the issue was not a concern because the bank board has been following Act 114, a transportation project ranking system set up by lawmakers in 2007 to reduce political influence in road building. Road and bridge projects are supposed to be ranked and rated by the system, but infrastructure bank projects and new construction are not included in the rankings, according to news reports.

In addition to I-526, the interstate upgrade list includes roads in Greenville, Lexington, Richland, Spartanburg and Cherokee counties.

Environmentalist Dana Beach, founder of the South Carolina Coastal Conservation League, attended the meeting. He expressed support for the interstate upgrades.

“I think it's great. Their priorities are appropriate. They make sense to me,” Beach said.

He urged the infrastructure bank board to follow the DOT recommendations for interstate improvements. If that does not happen, “Everyone in the state will understand how broken the system is,” he said.

Beach said it made sense to apply the more than $400 million allotted for the I-526 completion on Johns and James islands to the interstate upgrades instead.

The DOT uses a system to rank interstate upgrades that includes how much traffic a highway is carrying relative to its capacity, the number of accidents and fatalities, truck traffic, pavement condition, financial viability, environmental impacts and economic development. It assigns the greatest weight in the rankings, 30 percent, to the volume of traffic relative to capacity. Next is 20 percent for public safety. The rest of the factors have a weight of 10 percent, Patton said.

Several more pieces of the puzzle will have to fall into place before I-526 will get the funding needed to ease its clogged traffic. Next Thursday, the DOT Commission will meet to consider approval of the interstate upgrade priority list presented by agency staff. It will also vote on approval for the 2014-2019 State Transportation Improvement Plan, which includes federal funding for I-526 and the other recommended interstate upgrades.

After the DOT vote, the list of interstate upgrades next goes to the bank board and the Joint Bond Review Committee for a vote. Leonard said he anticipates a vote on the projects in the first or second week of September. In October, the package should be ready for consideration by the bond committee, he said.

Along their most-traveled sections, both I-526 and Interstate 26 have seen increased congestion since 2006, but the problem has been worse on I-26. The 2012 daily traffic count of 151,400 vehicles on I-26 from the U.S. 52 Connector to Ashley Phosphate Road is 25 percent higher than it was in 2006, according to DOT figures.

From 2006 to 2012, the busiest section of I-526, from West Montague Avenue to I-26, had an 8 percent increase in traffic to 86,000 vehicles daily.