The Charleston Metro Chamber of Commerce this week released the results of a poll that said 61 percent of those surveyed supported the completion of Interstate 526 across Johns and James islands.

But the survey included the voices of only about nine people from Johns Island — the primary base of the opposition.

It was the latest of several polls and surveys conducted over the years about the controversial highway extension, yielding varied and sometimes contradictory results, and no clear consensus on how much support the project has.

Mary Graham, the chamber’s chief advancement officer, said her group hired First Tuesday Solutions in Columbia to conduct a poll to gauge where county residents stand on the highway extension. The chamber strongly supports the completion of I-526.

Graham described the poll of 301 registered Charleston County voters as “a small but statistically significant sample.”

Luke Byars, managing partner of First Tuesday Strategies in Columbia, said that of the people surveyed: 32 percent came from Mount Pleasant; 20 percent from James Island; 15 percent from North Charleston,; 4 percent from the Charleston peninsula; 3 percent from Johns Island; and 24 percent from other places in the county.

“It’s valid,” Byars said of the poll. “It’s a snapshot at the time. It could be different today or tomorrow.”

Johns Island resident Rich Thomas, a member of the grassroots opposition group Nix 526, said he thinks the poll includes very little representation from Johns Island, “the area that’s going to be most devastated by the road project, and the development by chamber members that will follow.”

And, he said, nearly half of the responses come from people in North Charleston and Mount Pleasant, who won’t be affected by the road.

The survey asked people to rank the top three issues facing Charleston County from a list of six choices, the first of which was “traffic congestion.” Then, respondents were asked if they favored or opposed the completion of I-526.

At a heated Charleston County Council meeting about a possible half-cent sales tax increase Thursday, council members explored the idea of asking voters in a separate ballot question whether they supported the completion of I-526. But the group ultimately voted against several proposed ways of doing that.

It’s not the first time the group considered asking county residents to weigh in.

In August 2012, at the urging of Councilman Vic Rawl, Council considered putting the same question on the ballot. But only Rawl and Elliott Summey supported the plan, so it never came before voters.

At the time, both the Coastal Conservation League, a group fighting the highway extension, and the chamber, supporting the extension, were opposed. The league had concerns about how the question might be worded on the ballot, and the chamber was worried about not having enough time to launch a public education campaign to gain support.

A series of public hearings the state Department of Transportation conducted in 2010 as part of a federal approval process for the I-526 plan found the majority of people were opposed to the completion of the road.

But in September 2012, at the urging of then-House Speaker Bobby Harrell, the Transportation Department commissioned the University of South Carolina’s Institute for Public Service and Policy Research to conduct a poll on I-526. That survey found that 72 percent of those who responded were in favor of extending I-526 and only 28 percent were opposed.

Reach Diane Knich at 843-937-5491 or on Twitter @dianeknich.