South Carolina’s business leaders say legislators must pass a bill in the coming weeks that raises at least another $600 million a year for road and bridge work.

With just 24 days left in the legislative session, the South Carolina Chamber of Commerce and Manufacturers Alliance sent legislators a letter urging action. While the groups lay out a broad, five-point plan, they’re not picky on the specifics. What’s unacceptable is for the session to adjourn without a deal, said Ted Pitts, the chamber’s president and CEO.

“It’s way past the critical point. We need them to start moving now,” Lewis Gossett, the alliance’s president and CEO, said Monday via cellphone, as he dodged a huge pothole on Interstate 26.

The Department of Transportation has said it needs more than another $1 billion annually over 20 years to bring roads to good condition. The business groups are seeking at least $600 million through diversified sources — noting that as vehicles’ fuel efficiency increases, gas taxes will bring in less revenue.

Deplorable road conditions affect the state’s image and ability to attract business, said Jack Sanders, president of Hartsville-based Sonoco, which has some 200 trucks on South Carolina’s roads at any given time. The company says it spends millions yearly on truck repairs and lost time for detours around unsafe bridges.

Like other business executives, Sanders said road conditions are part of any discussion on whether to expand in South Carolina.

“We are one of the fastest-growing states. If we’re going to continue that wonderful growth, somehow, some way we have to widen our roads and repair our roads,” said Brian Newman, president of Honda of South Carolina, who worries about parts getting damaged on rough roads before arriving at his Timmonsville plant.

Progress could occur this week.

The House is expected to debate a bill Wednesday that would generate another $400 million annually for roadwork. It also cuts most taxpayers’ income taxes by $48 yearly. A bill up for debate in the Senate would generate roughly $800 million annually for roadwork but doesn’t address income taxes.

The House’s income tax provision is an attempt to escape Gov. Nikki Haley’s veto pen. But the threat looms, regardless.

Haley had repeatedly promised to veto any increase in the gas tax. In January, she offered to sign a 10-cent increase, but only if it’s accompanied by deep cuts to personal income taxes. Her plan would cut general fund revenue by $1.8 billion annually. But legislators of both parties balked, arguing that could necessitate deep budget cuts in education, health care and other services.

“What we need is money for roads,” said Rep. Gary Simrill, R-Rock Hill, chairman of the House panel that’s worked on a plan since last fall. “A roads bill is not the place to cover comprehensive tax reform.”