Even as reverberations from a proposed tax hike of nearly $1 billion for education roll through Colorado, another tax hike proposal is rumbling down the pike.

Called MPACT64, the group behind the proposal includes four regional organizations; Metro Mayors Caucus, Progressive 15, Action 22 and Club 20.

The organization is eyeing ways to fix Colorado's roads and chief among the proposals is a sales tax increase of 0.7 percent, which would raise about $600 million for the state's troubled transportation system.

"We started on this a year and a half ago not knowing the school finance act was coming," said Cathy Garcia, president and chief executive of Pueblo-based Action 22, which represents the southern part of Colorado. "We were going to put it on the ballot this year, but it was suggested that we not do that, which I agree."

After the November election, Garcia said the group plans to do a second round of polling to get additional input.

Polling in November of 2012 indicated that the most feasible fund-raiser would be the 0.7 percent sales tax, Garcia said.

"Action 22 felt that 0.5 percent would be better, based on what we were hearing from southern Colorado, but in order to make a big dent in our transportation needs, 0.7 would be the best way to go," she said.

There's no question of the need. According to MPACT64, more than half of the state highways are in poor condition.

At the same time, the state's population is growing, and so are the miles traveled.

Over the next 20 years, the population of Colorado is expected to grow 48 percent to 7.4 million, the miles traveled will climb 64 percent to 44.9 billion and traffic delays will jump by 158 percent, MPACT64 says.

That 17-minute delay on the road will grow to 44 minutes.

The main revenue generator for transportation in Colorado is the state's motor fuels tax of 22 cents per gallon.

After funds for the Colorado State Patrol and other Department of Revenue needs are pulled off the top, the remainder is shared by the Colorado Department of Transportation, 64 counties and 271 municipalities.

That tax was last raised in 1991 and despite a growing population, more efficient cars are keeping the revenue from growing.

The state transportation department pegs shortfalls of $772 million a year to fill urgent transportation needs.

As fuel economy has improved for all kinds of vehicles, the effectiveness of fuel taxes has waned in every state that depends upon them. The number of gallons of fuel consumed hasn't grown nearly as fast as the number of vehicle miles traveled, so many states are looking for a way, other than fuel taxes, of paying for road improvements.

"Input is needed," Garcia said. "Nobody likes taxes, but we need roads. In rural Colorado, we need shoulders, we need passing lanes. In Colorado, we need the infrastructure in order to generate business development and new jobs."'