Coloradans voted in 2005 for a five-year time-out on TABOR refunds. The Democrats’ proposal would make that permanent if approved by voters, Becker said.

Becker called it “a common sense first step,” but not a permanent solution, to funding schools and roads that have been underfunded for years because of TABOR which requires voter approval to raise taxes.

Democratic Sen. Lois Court of Denver and Republican Sen. Kevin Priola of Henderson, who joined Becker in announcing the initiative, said they hoped to build bipartisan support in the Democratic-controlled Legislature. Becker read a message from Democratic Gov. Jared Polis endorsing it.

Colorado voters consistently have rejected ballot measures asking them to raise state taxes for education and other priorities. In November, they defeated an education tax hike and competing measures to raise money for the state’s deteriorating roads.

TABOR, a constitutional amendment, allows government to ask voters to raise taxes or keep excess revenue, and many local municipalities have done so. In November, voters in suburban Lakewood authorized the city to keep excess revenue for public safety and other purposes.

TABOR sets an annual revenue limit that can trigger tax refunds based on a formula that involves population and inflation. It’s blamed by many Democrats for contributing to a $9 billion backlog in road projects and a multimillion-dollar debt to schools – all at a time when Colorado’s economy is one of the nation’s strongest.

Colorado Republicans, in contrast, credit TABOR and its tax limits for the strong economy.

Republicans began this legislative session wanting to build on a bipartisan effort last year that could generate $2.8 billion for transportation through bonding and direct spending. That measure will go before voters in November. If it fails, a 2017 law kicks in authorizing $1.9 billion in bonding for roads.

Priola said he hopes to generate Republican support for Wednesday’s initiative. He noted that Colorado hasn’t raised its 22-cents per gallon gasoline tax, a primary funding source for roads, since 1993.

“The power of TABOR is that you can go to the voters and let the voters decide,” Priola said.

The measure approved by voters in 2005, known as Referendum C, allowed the state to hold onto revenue that exceeded the state’s TABOR cap for five years.

Transportation advocates, such as Sandra Hagen Solin of Fix Colorado Roads, said Becker’s proposal is a “cherry on top” of anything we can get in funding but not the solution.

Still, she said, “We’re encouraged by any effort to direct additional funds to transportation.”

The Colorado Department of Transportation estimates it needs $9 billion over the next decade for its wish list of major road and bridge projects. The 2019-20 state budget scheduled to be introduced next week includes about $30 million for transportation, which Solin called a drop in the bucket.

She doesn’t expect to see transportation to rise on Polis’ priority list, at least this year.

Estimates on how much would be available from Becker’s “Son of Ref C” measure differ.

The governor’s Office of State Planning and Budgeting has a rosier projection of around $350 million in 2019-20 and as much as $700 million the following year.