A group of regional chambers of commerce in both the Twin Cities and outstate Minnesota came out Wednesday in support of new sources of revenue to pay for road, bridge and transit projects, although the group stopped short of explicitly calling for gas tax or vehicle registration increases.

"Investment in transportation is critical to Minnesota's competitiveness, so we also support an increase in revenue that allows us to properly plan and build a transportation system that will ensure regional competitiveness, vitality and economic growth in our state," read a letter to legislative leaders signed by the presidents or executive directors of regional business groups including chambers of commerce in Minneapolis, St. Paul, Duluth, Mankato and Marshall.

The group did not specify what type of transportation revenue enhancements they would prefer. Gov. Mark Dayton and Senate Democrats are pushing for a new type of per-gallon fuel tax and an increase in vehicle registration fees to fund road and bridge construction, along with a Twin Cities metro-area sales tax increase for transit.

While both Democrats and Republicans at the Capitol support a transportation spending boost between $7 billion and $11 billion over the next decade, divisions have sprung up over how to pay for it. GOP lawmakers have stood in unison against the gas tax proposal and other new revenue sources.

Late last month, an analysis of Minnesota's transportation funding needs, funded in part by the Minnesota Chamber of Commerce and Minnesota Business Partnership, argued that the total spending needs have been overstated. The analysis alleged that those spending estimates, which trace to a transportation panel appointed by Dayton, over-estimated the impact of inflation in estimating total costs of upgrading transportation infrastructure.

A House-Senate transportation conference committee started meeting this week. How much to spend on transportation, and where to get the money, is likely to be one of the top discussion points as Dayton and legislative leaders negotiate a final deal to end the session.

The letter to lawmakers from the regional chamber leaders can be read here.