LANSING, MI -- Gov. Rick Snyder's proposal to raise $1.2 billion a year in additional revenue for Michigan roads hit an early speed bump this week, as two high-profile members of his own political party questioned the main lynchpins of the plan.

Republican Senate Majority Leader Randy Richardville of Monroe said Wednesday that he and other lawmakers could have "a real problem" raising gasoline taxes and vehicle registration fees, suggesting that they will "be pushing things off the table and then looking to say whether there are better ways, more creative ways."

Richardville, who has sat down to discuss road funding with the governor and House Speaker Jase Bolger, reiterated his position on Thursday, telling the MIRS subscription newsletter that, in his opinion, both ideas may already be off the table.

Secretary of State Ruth Johnson, meanwhile, has spoken out against an increase in vehicle registration fees, which her office processes.

"We have too many families who already are struggling to get by," the Oakland County Republican told MLive on Wednesday. "Those fees would be on top of what they're already paying, and it's difficult for many of our residents."

Snyder, who first highlighted the need for infrastructure attention in 2011, shared his road funding proposal with lawmakers last week as part of his latest executive budget, suggesting that the state can avoid a $25 billion construction bill by investing $12 billion in repairs over the next ten years.

To raise those funds, the governor proposed increasing the state's 19-cent gasoline tax and 15-cent diesel tax to the wholesale equivalent of 33-cents per gallon, while bumping vehicle registration fees by 60 percent for passenger vehicles and 25 percent for heavy trucks.

All told, the administration says increased taxes and fees would cost the average Michigan family $120 a year per vehicle. But, Snyder suggested, improving roads could save residents $80 per year in vehicle repair costs and even save lives.

"The governor's initiative is based on the fair concept of user fees, which means that people who drive the most or have higher valued cars will contribute more to restoring our deteriorating roads," spokesman Kurt Weiss said Thursday evening when asked about Richardville's comments.

"But the governor recognizes that there may be other ideas on how to achieve this critical goal. The governor looks forward to working with lawmakers to address this vital issue, which has been ignored for too many years. At the end of the day, though, doing nothing is not an option. We can't sacrifice lives and jobs by taking the easy way out and refusing to deal with this problem."

The legislature is expected to tweak and modify the governor's budget proposal over the course of the next several months before returning it to his desk for signature. Transportation funding is expected to be one of the key areas of debate and is especially urgent due to the approaching construction season.

Richardville last month introduced a joint resolution seeking to fund road repairs by raising the state's sales tax by two percent. The plan, which also calls for elimination of the gas tax, would require 2/3 majority support in the legislature and voter approval at the next statewide election.

Democrat Jim Ananich of Flint announced yesterday that he is preparing to introduce a series of bills that would protect Michigan taxpayers as road funding discussions continue. His legislation seeks to end tax loopholes for corporations such as BP and Exxon, provide a sliding-scale tax credit for working drivers and retain language giving a preference to American-made construction materials and workers.

"Everyone agrees fixing our roads and investing in jobs is important, but we also need to make sure we're doing what's right for Michigan's hardworking taxpayers," Ananich said in a release. "These common sense measures deserve to be a part of the debate moving forward."

Members of the Senate and House transportation committees met in joint session twice this week to discuss the need for road funding and possible revenue sources. Republican Rep. Wayne Schmidt of Traverse City, who led Thursday afternoon's joint hearing, said that "nothing's off the table in the House. We continue to look at (the governor's proposal). That's all there is to it."

House Speaker Jase Bolger has not yet backed any road funding solution, but he hasn't dismissed any either. The Marshall Republican wants to explore all cost-savings opportunities before considering new taxes or fees.

"He wants us to make sure we are using every single dollar as effectively and efficiently as possible because going to the taxpayers for more money is the last answer we should consider," said spokesman Ari Adler. "There is a billion-dollar question in this state that must be answered, but we must be careful not to jump to any particular answers before all the questions have been asked."

Jonathan Oosting is a Capitol reporter for MLive Media Group. Email him at joosting@mlive.com or follow at twitter.com/jonathanoosting.