Republicans in the State Senate introduced a new bill Wednesday aimed at forcing Sound Transit to make changes when it comes to car-tab fees.

The proposal is the latest legislative response to public outcry over costly car-tab fees happening as a result of the tax increase put in place after the passage of Sound Transit 3.

Senate Bill 5893 would require Sound Transit to take Manufacturer's Suggested Retail Price out of the formulas used to calculate car-tab fees. If Sound Transit refuses to do so, it would no longer be able to contract with the Department of Licensing to collect motor vehicle excise taxes.

"The last thing we want is that a state agency would be involved in collecting that unconstitutional and unfair tax," said Sen. Steve O'Ban, R-University Place. "So what this bill does is it instructs the Department of Licensing that they may no longer contract with Sound Transit if Sound Transit is going to insist upon continuing to collect that unfair, unconstitutional MVET tax that is based on the MSRP and not on the real value of our constituents' vehicles."

O'Ban says the bill is essentially using the Department of Licensing as leverage, because lawmakers know that Sound Transit does not have the infrastructure in place to collect the taxes without DOL's help.

"It's really clear, we don't want the State of Washington to be the bagman for a dishonest process," said Sen. Dino Rossi, R-Sammamish.

He and O'Ban are two of the 21 Republican senators who've signed on as co-sponsors of the bill. That's almost the entire Majority Coalition Caucus.

"Getting that kind of support right out of the box tells you just how important it is to all of us," said Sen. Randi Becker, R-Eatonville, who is the Majority Coalition Caucus Chair. "This topic has generated more emails and calls than any topic I've had in the past, ever. So this is telling me just how frustrated people are."

Becker says the support of the caucus is significant because it shows their commitment to the bill and a willingness to exempt it from the cutoff deadline and keep it moving forward in the legislature.

A spokesperson for Sound Transit told KING 5 they were still reviewing Senate Bill 5893, since it was just announced on Wednesday.

"I suspect we will also have Democrats that will support this bill," said O'Ban. "I think our Democratic colleagues are also getting emails and I expect them to also be concerned about their constituents and want to sign onto this bill and support this bill through the process."

But Democratic Senator Marko Liias, D-Lynnwood, said he's not so sure that will happen.

"I think we can't lose sight of the mission at the end of the day. The mission of Sound Transit Three at the end of the day is to get light rail to where it needs to be to connect people to their jobs," said Liias.

He said he did not feel like a threat to end DOL's contract with Sound Transit was the most effective way to address the issue of pricey car-tab fees.

"To involve DOL in this, I just think the idea that we have to leverage another public agency that's trying to do their job just isn't constructive," he said. "I think introducing a bill that tries to make a political point late in the legislative session on an issue that people are mad about, it wins if you're trying to make a political point, but I'm trying to solve the problem which is give taxpayers that have concerns an answer and try to find the best path forward."

With or without Democratic support, Senate Bill 5893 will likely still pass in the Republican-controlled Senate.

Meanwhile, the Democratic-controlled House is considering several Sound Transit-related bills of its own, that take a different approach to addressing the issue of skyrocketing car-tab fees.

House Bill 2147 would use a more current motor vehicle depreciation schedule that would reduce the taxable value of vehicles and in doing so, reduce car-tab fees. House Bill 2150 would require Sound Transit to update taxpayers on whether its projects are on-budget and on-time.

Sound Transit Three is a 25-year, $54 billion transit package that voters approved last fall. It will expand mass transit within the Sound Transit District in King, Pierce, and Snohomish counties with a range of light rail, commuter rail, and bus connections.