PORTLAND — A Maine Turnpike spokesman says it’s too early to interpret the results of a consultant’s study into future demands on the toll highway’s southern leg.

But the preliminary study says the 36 miles between South Portland and York is overloaded and will fail to meet the demand of traffic in a decade unless changes are made.

“We’re not interpreting this information because we just think it’s way too early,” said turnpike spokesman Daniel Paradee. “We’d like to have all the information considered as a final package at the end of the process.”

The turnpike authority has formed a 24-member Citizens Advisory Committee to oversee the work of the consultant and reach a consensus. The committee is composed of groups with differing views on traffic management.

The turnpike authority is scheduled to make recommendations to the Legislature in December.

Maine voters in 1991 rejected a plan to widen the southern leg of the turnpike from four to six lanes. In doing so, they also imposed a law that requires officials to explore alternatives to highway construction.

The study by consultant Vanasse Hangen Brustlin Inc. of Watertown, Mass., will conclude with a cost-benefit analysis of various options for improving turnpike traffic, ranging from widening the southern end to taking measures to reduce traffic at peak times.

The preliminary report says drivers’ freedom to maneuver on the turnpike is restricted by other traffic, and that minor incidents can cause serious congestion. That level of service falls short of the recommended standard for roadway design.

The Natural Resources Council of Maine, which opposed the turnpike widening in 1991, questions some assumptions used by the consultant to reach its conclusions and has hired its own consultant to review the data.

But Senate President Jeffrey Butland, R-Cumberland, said the study and previous ones show that the turnpike needs to be widened.

“The turnpike people have bent over backward to work in good faith with all of the participants so when a conclusion is made to widen the turnpike it will be unassailable. They have far greater patience than I do,” Butland said.