The government is expected to spend hundreds of millions — if not billions — of dollars on infrastructure in the Baton Rouge region in the coming decades, and Tuesday, officials from five area parishes began the process of divvying up the pot.

Mayors and parish presidents gathered to begin discussing projects they’d like to see implemented through the year 2042.

By U.S. law, metropolitan areas must establish a planning agency that follows certain procedures to apply for federal transportation funding. One reason is to ensure that projects do not negatively affect air quality. While the Baton Rouge area has had projects delayed for contributing to poor air quality, none have ever been outright denied, said Capital Region Planning Commission Executive Director Jamie Setze.

Tuesday, he told officials from East Baton Rouge, Ascension, Livingston, Iberville and West Baton Rouge parishes that it is time to extend the Metropolitan Transportation Plan from 2037 to 2042 and make any amendments to the document.

It is expected to take about a year to hold all the necessary public meetings and determine which projects are most-needed and can be built with available funding.

The local officials said they haven’t yet determined which specific projects they’ll lobby for, though Livingston Parish President Layton Ricks said he’ll push to get as much allocated for his parish as possible.

Government entities in the area are projected to spend almost a billion dollars on overlays, new roundabouts, additional lanes and other roadwork in the current phase, which began in 2013 and runs through next year.

The plan includes $1.1 billion in proposed projects scheduled for construction in the next phase between 2018 and 2027, including a $276 million proposal to widen Interstate 10 in Ascension Parish as far south as the Sorrento exit at La. 22.

Ascension Parish does not have a local road plan, and Parish President Kenny Matassa said he wants to create a long-term master plan as the regional project list is updated.

Matassa wants to build service roads along the length of the interstate to encourage commercial growth and urban development. He hopes a master plan with future road construction can be used when developers want to build on vacant land. The parish may be able to offer incentives to keep them from building in areas planned for future roads, then purchase the plots when the parish is ready to build.

East Baton Rouge Parish officials didn’t identify any specific routes they hope to improve, though Mayor-President Kip Holden said an interstate loop — expensive and much-resisted — won’t be part of the discussion. He and his staff mostly were concerned whether the regional plan would be able to accommodate any local initiatives if the city-parish tries to spearhead any future construction programs like the existing Green Light Plan. Setze confirmed that would be possible.

In the coming weeks, local officials and residents will have additional opportunities to weigh in on roadwork they hope to see down the road. A draft is expected to be released for public comment by spring, and the final plan is scheduled to be adopted around July 2017.

Follow Steve Hardy on Twitter, @SteveRHardy.