Maine’s top transportation official will meet with lawmakers Tuesday to discuss a report that calls for the state to double its annual spending on bridge maintenance or face the much greater cost of replacing bridges in the future.

Transportation Commissioner David Bernhardt will meet with the Legislature’s Transportation Committee to address a department study that recommends increasing annual spending on bridge maintenance from $70 million to $140 million.

The Keeping Our Bridges Safe report was completed by a team of bridge experts in the private and public sectors under the direction of Joyce Taylor, chief engineer of the Maine Department of Transportation.

The group says that basic preventive work, such as washing bridges, painting beams and replacing joints, prevents bridges from deteriorating prematurely.

“We can conclude that investing in preservation now is key to saving significant dollars in the future,” the report said.

The state maintains 2,744 bridges. At current funding levels, the report found, about 40 percent of those bridges will deteriorate over the next 25 years to such poor condition that replacing them or doing expensive rehabilitation will be the only options for keeping the public safe.

If the state doubled its annual spending on bridge maintenance over that period, however, only 15 percent of the state’s bridges will need to be replaced or undergo rehabilitation, the report said.

The Maine Department of Transportation has yet to identify a funding source for the additional $70 million. Ted Talbot, the department’s spokesman, said some of the money could come from a state bond, but the department may also be looking for increased federal dollars in the long term as well as redirecting funds that are now being spent elsewhere.

Rep. Andrew McLean, D-Gorham, House chairman of the Transportation Committee, said it’s unlikely that Congress will provide the state more money by increasing the gas tax and that Maine’s highway maintenance is also badly underfunded.

“There is only one pot of money for all of this,” he said. ” If you are taking money from roads to fix bridges, how are the roads going to get fixed?”

The Department of Transportation’s total annual budget is about $600 million, including $165 million from the federal government for highway and bridge projects and $30 million for non-highway projects, such as rail and aviation.

The number of structurally deficient bridges in Maine increased from 14.8 percent in 2012 to 15.2 percent in 2013, according to the report. That increase stands in contrast to the trend nationally, where the number of structurally deficient bridges has been declining steadily since 2001 and stood at 10.7 percent in 2013.