AUGUSTA, Maine — Faced with rising costs and shrinking revenues, the Maine Turnpike Authority has decided to push back a widening plan for the Portland area and move up by a year a planned toll increase.

Paul Violette, executive director of the turnpike authority, delivered the sobering news to the Joint Committee on Transportation on Wednesday. Violette said the $150 million widening plan would be scaled down and the 23 percent rate increase planned for February 2010 would be moved up to February 2009.

“As we’re all aware, there have been some changes in the way people are moving about,” he said.

Violette said construction costs had increased 38 percent in the past three years while revenues had declined by 2 percent. He said personnel cuts already had been made as toll takers were replaced by automated screeners but that tolls needed to be increased to offset growing costs.

As a result of the economic factors, Violette said the 10-mile-long, $150 million widening project would be delayed until 2016, although work on the bridges and abutments on that stretch of road would continue. He said the bridge and abutment part of the project would cost $75 million.

Violette said ridership forecasts indicate numbers will be flat in the foreseeable future. Implementing the toll increase was critical in order to carry out the authority’s planned highway and bridge rehabilitation programs in the face of skyrocketing construction costs.

Violette said ridership was off dramatically this summer, especially on the weekends. He said traffic was down 8 percent during September, but increased 9 percent over the Columbus Day weekend. He said forecasters predict modest increases once the price of fuel stabilizes.

“There will continue to be growth, but at a more modest rate of growth,” he said.

In the past three years, the cost of road salt has increased 83 percent, paving increased 82 percent and diesel fuel increased 117 percent, he said.

“No one likes a toll increase, but we don’t do anyone a favor by allowing Maine’s most important highway and its bridges to deteriorate to a point where safety is compromised and repairs become even more expensive,” he said.

The toll increase will amount to about $20 million.

Current tolls for passenger cars work out to 3.7 cents per mile along the 110-mile-long turnpike. The February toll hike will increase that figure to 4.5 cents per mile. At the same time, the rate for trucks will increase to 15 cents per mile.

“I’m sure we’re going to be hearing from the truckers,” said Rep. William P. Browne, R-Vassalboro.

Sen. Dennis Damon, who is co-chairman of the Transportation Committee, described the twin pressures of lower revenues and higher costs as the gaping jaws of an alligator.

“The alligator’s mouth is opening wider and wider,” the Trenton Democrat warned at Wednesday’s meeting.

Violette said Maine is not alone in raising its tolls, saying similar increases are being imposed on other highways including New Jersey’s turnpike and Garden State Parkway. Increases have been under discussion in Massachusetts, and New Hampshire raised its turnpike tolls last year.

Violette also reported on plans to relocate the York toll plaza. He said the proposal was vehemently opposed by the town and the authority had asked its consultant to take another look at expanding the existing plaza. He assured committee members that they would be informed immediately when the results are in.

“We want to work with that community and see what other options there might be,” Violette said.

The Associated Press contributed to this report.